Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

At least 163 records · Page 9Linked to original sources

PubMed2000

[Clinical study of shengxue mixture in treating aplastic anemia].

OBJECTIVE: To observe the clinical effect of Shengxue mixture (SXM) in treating aplastic anemia, and studied its mechanism. METHODS: Eighty-four patients of the treated group, those with Spleen-Kidney Yang deficiency Syndrome and Spleen-Kidney Yin deficiency Syndrome were treated with SXM-A and SXM-B respectively, and 30 patients of the control group were treated with Stanozolol. The clinical effect and several experimental parameters were also observed. RESULTS: The basic cure rate, remission rate, total effective rate of the treated and control group were 21.43%, 27.38%, 86.90% and 3.33%, 20.00%, 56.67% respectively, the difference between 2 groups was significant (P < 0.05, P < 0.01). The effect of the treated group was obviously better than that of the control group. While the patients' symptoms were alleviated, the peripheral blood cells increased, the ratio of T lymphocyte subsets tended to balance, the level of natural killer cells activity increased, interleukin 2 reduced, and the reproduction of the bone marrow were markedly improved in most of the patients treated by SXM. CONCLUSION: SXM is an effective and safe drug for aplastic anemia. Its mechanism might be regulating the immune function, which facilitated the recovery of the bone marrow hematopoiesis function.

Adolescent↗

PubMed2000

[Damage to intra- and extrahepatic bile duct after hepatic artery embolization].

OBJECTIVE: To study the pathogenesis, treatment and prevention of bile duct damage arising from hepatic artery embolization. METHODS: Five patients with intra- and extrahepatic biliary damage resulting from hepatic artery embolization. Of these patients, 4 were due to hepatic artery embolization for hepatic haemangioma, and 1 was due to injecting TH (methacrylate) compound into the hepatic artery during operation. The hepatic artery was injected with ethanol so as to evaluate liver damage in experimental rats. RESULTS: All patients were found to have damage to intra- and extrahepatic bile duct at the hilum with biliary hepatocirrhosis; 4 of them received intrahepatic bile duct jejunal anastomosis and bile duct stent. Experiment result revealed obliteration of the bile duct and necrosis of the liver around the portal tract area. CONCLUSIONS: Arterial embolization of hepatic haemangioma may cause severe biliary damage.

Adult↗

PubMed2000

[Evidence for TCR Vbeta clonal expansion T cells in a patient with cGVHD after unrelated donor BMT].

OBJECTIVE: To investigate the distribution and clonal expansion of TCR Vbeta subfamily T cells in patients with cGVHD after unrelated donor bone marrow transplantation (BMT). METHODS: The CDR3 of 24 TCR Vbeta subfamily genes were amplified from peripheral mononuclear cells of a patient with cGVHD after unrelated BMT. RT-PCR was used for detection of the distribution of TCR Vbeta repertoire, and the PCR products were further analyzed by genescan technique for the CDR3 size, to evaluating clonality of the detectable TCR VbetaT cells. RESULTS: Only 8 Vbeta subfamily T cells could be identified in the patient, clonal expansion T cells could be found of Vbeta2, 3, 8 and 13 subfamilies. CONCLUSIONS: The skew distribution and clonal expansion of TCR Vbeta subfamily T cells could be found in the patient. It may relate to the initiation of cGVHD.

Acute Disease↗

PubMed2000

[Quantitative determination of EAIgG by ABC-ELISA and its clinical significance].

OBJECTIVE: To explore a method for diagnosis of autoimmune hemolytic anemia (AIHA) and evaluate its clinical significance. METHODS: Erythrocyte associated IgG (EAIgG) was quantified in 60 healthy people, 44 patients with warm antibody AIHA (WAIHA), 108 non-immune anemia and 44 other immune diseases (total 256 cases) by using ABC-ELISA were estimated. RESULTS: EAIgG in WAIHA patients were significantly higher than those in other groups (P < 0.01). In the 44 WAIHA patients, 38 were Coombs positive and 6 Coombs negative. EAIgG in Coombs negative was significantly high. The dynamic changes of EAIgG in 12 WAIHA patients were observed during treatment. When patient's condition got better, Hb and RBC increased and EAIgG decreased. CONCLUSION: Quantitative detection of EAIgG is an index in the diagnosis of WAIHA, especially in AIHA with negative Coombs' test. It is also a useful factor for evaluating therapeutic effect and prognosis in WAIHA.

Adolescent↗

PubMed2000

[Detection of antidepressant and antipsychotic drugs in human hair and evaluation of the results].

The presence of therapeutic drugs in the hair of psychiatric patients was investigated, and the method for simultaneous determination of antidepressant and antipsychotic drugs by GC/NPD and GC/MS was also established. Eight different psychotroic drugs were detected from the hair of 32 subjects, and chlorpromazine and clozapine concentrations in the hair were found to be dependent on the dosage and the correlation coefficients were 0.8047 (P < 0.001, n = 16) and 0.7097 (P < 0.001, n = 16) respectively. Segmental analysis demonstrated that there was a correlation between the subject's drug exposure history and the distribution of drug along the hair shaft.

Adult↗

PubMed2000

[Characterization and phylogenic analysis on a new isolate of genus Rhodocista].

A strain of purple non sulfur bacteria was isolated from waste water plant in Beijing. It is phototaxic, and can converted the vibrioid cells into thick-wall cyst. Internal synthetic membrane is present as lamellae. It has a low absorption maxima at 798 nm. and require thiamine and vitamin B12 as growth factors. It can use succinate as carbon and energy source, but glucose can not be used. It can not grow in 3% NaCl and had Q-9 as major quinone. The 16S rRNA gene was amplified, cloned and sequenced. A phylogenic tree was constructed on the basis of the 16S rDNA sequences. It showed that the previously known member of the genus Rhodocista, Rc. centenaria, is the nearest neighbor to strain 3-p. The level of binary sequence similarity between Rc. centenaria and strain 3-p of 95%, and their phenotypic differences and genetic DNA-DNA relatedness of 56%, shows they are different species of Rhodocista. A new species name, Rhodocista pekinense, was proposed for strain 3-p.

Base Sequence↗

PubMed2000

[Phenotypic features and genetic diversity of strains of Rhodopseudomonas].

14 strains of purple non-sulfur bacteria and 3 type strains of Rhodopseudomonas were investigated by phenotypic characterizing, DNA-DNA hybridizing and DGGE analyzing. The characteristics of their morphology, structure and physiology show that 14 strains of isolates have the features of the genus Rhodopseudomonas: dividing asymmetrically by budding, lamellar intracytoplasmic membranes, presence of bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series. On the base of their differences in morphology, growth, carbon sources 14 strains can be divided into 2 groups: g-c group, T group. Parts of 16S rRNA gene were amplified by using a pair of primers: 341f-906r. Denaturing gradient gel electrophoresis(DGGE) of PCR-amplified fragment of rDNA indicated that they have 3 genetic types: 1 of them, including 6 of 8 strains of T groups is similar to that of Rps. rutila R1, the other 2 types, represented separately by 2 of T group or all the g-c group, were different from that of either of 3 type strains The Data of the DNA-DNA hybridization of 8 representative strains indicated that the differences between different types were enough to separate them into different species including 2 possible new species.

DNA, Bacterial↗

PubMed2000

[The application of epiglottis in laryngeal function reconstruction after partial laryngectomy].

OBJECTIVE: To observe the appliance value of epiglottis in laryngeal function reconstruction after partial laryngectomy. METHODS: Thirty-two cases of glottic and superglottic carcinomas of larynx had conducted partial laryngectomy and the laryngeal function was reconstructed using epiglottis from December. 1992 to January 1996. RESULTS: Nineteen of the twenty-one glottic carcinomas and five of eleven supraglottic carcinomas were decannulated and recovered with laryngeal functions. All the patients rehabilitated deglutition in 14-18 days after surgery. None presented complication of aspiration. CONCLUSIONS: Epiglottis has many advantages in partial laryngectomy and the laryngeal reconstruction. It is easy to approach, apply and heal in short period. It also prevents aspiration and improves the decannulation rate as well as the quality of life in partial laryngectomy patients.

Adult↗

PubMed1999

Waist circumference, waist:hip ratio, and risk of breast cancer in the Nurses' Health Study.

This study examined prospectively the associations of waist circumference and waist:hip circumference ratio with risk of breast cancer. A total of 47,382 US registered nurses who reported their waist and hip circumferences in 1986 were followed up through May 1994 for identification of incident cases of breast cancer. During 333,097 person-years of follow-up, 1,037 invasive breast cancers were diagnosed. In proportional hazards analyses, waist circumference was nonsignificantly related to risk of premenopausal breast cancer but was significantly associated with postmenopausal breast cancer after adjustment for established breast cancer risk factors (for the highest quintile of waist circumference vs. the lowest, relative risk (RR) = 1.34; 95% confidence interval (CI): 1.05, 1.72). When the analysis was limited to postmenopausal women who had never received hormone replacement therapy, a stronger positive association was found (RR = 1.88; 95% CI: 1.25, 2.85). After the data were further controlled for body mass index, the positive association was only slightly attenuated (RR = 1.83; 95% CI: 1.12, 2.99). Among past and current postmenopausal hormone users, no significant associations were found. Similar but slightly weaker associations were observed between waist:hip ratio and breast cancer risk. These data suggest that greater waist circumference increases risk of breast cancer, especially among postmenopausal women who are otherwise at lower risk because of never having used estrogen replacement hormones.

Abdomen↗

PubMed1999

Acousto-optical deflection-based laser beam scanning for fluorescence detection on multichannel electrophoretic microchips.

Laser beam scanning driven by an acousto-optical deflector (AOD) is presented for multimicrochannel laser-induced fluorescence (LIF) detection during microchip-based electrophoresis. While fast laser beam scanning for LIF detection on capillary or microchannel arrays can been achieved with galvanometric scanning or a translating stage, it can also be accomplished by using acoustic waves to deflect the laser beam in a manner that is dependent on the acoustic frequency. AOD scanning differs from other approaches in that no moving parts are required, and the scan frequency is faster than conventional approaches. Using a digital/analog (D/A) converter to provide addressing voltages to a voltage/frequency converter, rapidly changing the frequency input to the AOD allows the laser beam to be addressed accurately on a microchip. With the ability to change the frequency on the nanosecond time scale, scanning rates as high as 30 Hz for Windows-based LabView programming are possible, with much faster scan rates achievable if a microprocessor-embedded system is utilized. In addition to spatial control, temporal control is easily attainable via raster scanning or random addressing, allowing for the scanning process to be self-aligning. Since the D/A output voltages drive the scanning of the laser beam over all channels, the software can define addressing voltages corresponding to the microchannel centers and, subsequently, fluorescence data can be collected from only those locations. This method allows for flexible, high-speed, self-align scanning for fluorescence detection in capillary or microchip electrophoresis and has the potential to be applied to a number of applications.

Acoustics↗

PubMed1999

The roles of side chain and backbone in protein structure probed with glycine- and sarcosine-rich synthetic leucine zipper peptides.

The protein folding problem has long been a formidable challenge. Here we present a synthetic natural motif approach that exploits small preexisting structural models for the dissection of forces important in protein folding. An example for this approach is shown in the modification of a 31-residue leucine zipper peptide with the helix-breaking amino acid glycine and the hydrogen bond-breaking imino acid sarcosine. Circular dichroism and NMR experiments have shown that the glycine-modified leucine zipper peptide adopts a stable helical conformation similar to the native conformation while the sarcosine-modified leucine zipper peptide adopts a random coil conformation. These results provide valuable insight into the current controversy over the relative importance of long-range side chain-side chain interactions versus local backbone interactions in protein structure and suggest that the natural motif strategy may represent a useful model to study protein folding.

Amino Acid Motifs↗

PubMed1999

The Gelation of CO(2): A Sustainable Route to the Creation of Microcellular Materials.

Compounds with strong thermodynamic affinity for carbon dioxide (CO(2)) have been designed and synthesized that dissolve in CO(2), then associate to form gels. Upon removal of the CO(2), these gels produced free-standing foams with cells with an average diameter smaller than 1 micrometer and a bulk density reduction of 97 percent relative to the parent material.

Journal Article↗

PubMed1999

Sequence and characterization of cDNA encoding the motilin precursor from chicken, dog, cow and horse. Evidence of mosaic evolution in prepromotilin.

Motilin is involved in the regulation of the fasting motility pattern in man and in dog, but may have a different role in other species. Immunoreactive motilin has been demonstrated in several species, but the sequence is mostly unknown. The aim of this study was to isolate and sequence the cDNA encoding the motilin precursor from several mammalian species and from chicken. Total RNA was isolated from the duodenal mucosa of the chicken, dog, cow and horse. In each case single stranded cDNA was synthesized. Motilin cDNA fragments were amplified by PCR, ligated into a plasmid and cloned. Clones which were positive after screening with an appropriate (32)P-labeled probe were sequenced. The 5'- and 3'-ends were determined by the rapid amplification of cDNA ends (RACE) method. Analysis of the cDNAs revealed an open reading frame coding for 115 (chicken and cow), or 117 (dog and horse) amino acids. It consists of a 25 amino acid signal peptide, motilin itself, and a 68 (chicken and cow) or 70 (dog and horse) amino acid motilin associated peptide (MAP). As in all motilin precursors already sequenced (man, monkey, pig and rabbit), an endoproteinase cleavage site is present at Lys(23)-Lys(24). Comparison of all known sequences shows considerable identity in amino acid and nucleotide sequence of the signal peptide and motilin. However, the MAPs differ not only in length but also, more strongly, in amino acid and nucleotide sequence. Our study demonstrates that the N- and C-terminal regions of the motilin precursor have evolved at different rates, which is evidence for 'mosaic evolution'.

Amino Acid Sequence↗

PubMed1999

Two-dimensional freezing in the liquid-vapor interface of a dilute Pb:Ga alloy.

We report the results of x-ray reflectivity and grazing incidence x-ray diffraction studies of the liquid-vapor interface of a dilute alloy of Pb in Ga over the temperature range of 23-76 degrees C. Our data show that the liquid-vapor interface of this alloy is stratified for several atomic diameters into the bulk liquid and that a monolayer of Pb forms the outermost stratum of the interface. Over the temperature range of 23-56 degrees C, the monolayer of Pb is in an ordered hexagonal phase. At about 58 degrees C, this monolayer undergoes a first-order transition to a hexatic phase, which remains stable to 76 degrees C. An analogy between the observed transition and the first-order melting transition in a one-component classical plasma is suggested.

Journal Article↗

PubMed1999

A(2A) adenosine receptor deficiency attenuates brain injury induced by transient focal ischemia in mice.

Extracellular adenosine critically modulates ischemic brain injury, at least in part through activation of the A(1) adenosine receptor. However, the role played by the A(2A) receptor has been obscured by intrinsic limitations of A(2A) adenosinergic agents. To overcome these pharmacological limitations, we explored the consequences of deleting the A(2A) adenosine receptor on brain damage after transient focal ischemia. Cerebral morphology, as well as vascular and physiological measures (before, during, and after ischemia) did not differ between A(2A) receptor knock-out and wild-type littermates. The volume of cerebral infarction, as well as the associated neurological deficit induced by transient filament occlusion of the middle cerebral artery, were significantly attenuated in A(2A) receptor knock-out mice. This neuroprotective phenotype of A(2A) receptor-deficient mice was observed in different genetic backgrounds, confirming A(2A) receptor disruption as its cause. Together with complimentary pharmacological studies, these data suggest that A(2A) receptors play a prominent role in the development of ischemic injury within brain and demonstrate the potential for anatomical and functional neuroprotection against stroke by A(2A) receptor antagonists.

Aging↗

PubMed1999

Attachment of C-terminus of SDF-1 enhances the biological activity of its N-terminal peptide.

The N-terminus of stromal cell-derived factor 1 (SDF-1) is known to be a critical site for CXCR4 receptor binding and signaling. However, the functional role of other regions, in particular the C-terminal helix of SDF-1, has yet to be defined. In this study, we designed and synthesized a peptide model of SDF-1 containing its N- and C-terminal regions. The attachment of the C-terminus of SDF-1, which by itself had no activity in receptor binding and signaling, dramatically increased the effect of the N-terminal fragment in inducing chemotaxis and intracellular Ca(2+) influx in sup T1 cells compared with the peptide containing only the N-terminal sequence. The enhancement in activity was not due to the increase in receptor affinity as the N,C-terminal peptide did not show higher CXCR4 binding than the N-terminal peptide. On the other hand, the intracellular Ca(2+) influx activated by the N,C-terminal peptide, but not the N-terminal peptide, was completely abolished by the addition of heparin, suggesting that the C-terminal fragment of the peptide binds glycosaminoglycans (GAGs) and exerts an effect to modulate biological activity. These data raise the possibility that the C-terminus in native SDF-1 is one of interaction sites with GAGs and may be associated with biological function of SDF-1. Furthermore, this study demonstrates an approach for the design of novel agonists or antagonists of other chemokine receptors that possess enhanced biological activity.

Binding Sites↗

PubMed1999

The role of positively charged residues in CXCR4 recognition probed with synthetic peptides.

A high positive charge is the common characteristic shared by the beta-sheet region of stromal cell-derived factor-1 (SDF-1) and CXCR4 antagonists such as ALX40-4C consisting of nine D-arginines. This raises the question that the positively charged residues may play a role in recognition of CXCR4. To test this hypothesis, two studies were carried out using synthetic peptides. In the first study, peptide analogs possessing amino acid sequences from both the N-terminus and the beta-sheet region of SDF-1 were used as models to study the functional role of the beta-sheet region of SDF-1. The attachment of positively charged residues to the N-terminal peptide sequence of SDF-1 was found to enhance the ability of the peptides in CXCR4 binding and inhibiting CXCR4-mediated T-tropic HIV-1 entry. In the second study, two peptides containing nine arginines and the N-terminal signal sequence of SDF-1 were used as models to study the receptor binding mechanism of CXCR4 antagonists of high positive charges such as ALX40-4C. One peptide did not show signaling activity as indicated by the lack of calcium influx while another peptide induced unusual calcium influx distinct from that induced by the SDF-1 N-terminal peptide. In addition, the signal induced by the SDF-1 N-terminal peptide was inhibited by ALX40-4C. Therefore, the first study provides experimental support for the role of the highly positive beta-sheet region of SDF-1 in CXCR4 binding. The second study suggests that the binding site of ALX40-4C in CXCR4 may partially overlap with that of the SDF-1 N-terminal peptide. Both findings should be valuable for the design of SDF-1 agonists and antagonists.

Amino Acid Sequence↗

PubMed1999

Characterization of the sensitivity of side scatter in a flow-stream waveguide flow cytometer.

BACKGROUND: We previously reported a new optical configuration, in which both the side scatter and the fluorescence are collected using the index-guided, total internal reflection of a flow stream in air (the flow-stream waveguide). METHODS: Using a mixture of 0.202-microm and 0.093-microm diameter polystyrene beads, we have characterized the side scatter (SSC) sensitivity of a custom-built flow cytometer (miniFlo) which incorporates a flow-stream waveguide. RESULTS: The SSC-triggered SSC signal of 0.093-microm polystyrene beads in water was almost baseline resolved from the background. We also measured the SSC-triggered SSC signal of the same beads in water on our FACScan, which is a commercial unit with the conventional optical arrangement that uses a custom imaging objective to collect light from a sheath flow cuvette in perpendicular direction-the signal from 0.093-microm beads was not resolved from the background. CONCLUSIONS: The SSC sensitivity of miniFlo is one of the best reported in the literature. Cytometry 37:160-163, 1999. Published 1999 Wiley-Liss, Inc.

Flow Cytometry↗