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Biomedical subjects

Y Huang

Publications and source records attributed to Y Huang.

At least 559 records · Page 31Linked to original sources
PubMed1999

[The determination of anions of very weak acids by incompletely suppressed conductometric detection].

A novel method, incompletely suppressed conductometric detection, has been developed for the determination of anions of very weak acids. The principle of the method is discussed. The advantages of the method over the suppressed and nonsupressed methods for the determination of anions of very weak acids are also discussed theoretically. Results showed that the detection limits of the method for arsenous acid and boric acid were lower than those of nonsuppressed conductometric method. Being compared with suppressed conductometric method, the sensitivity was improved greatly. For 250 mg/L boric acid, 261- and 1002-fold increases in peak height and peak area were obtained, respectively. Within the linear range of the detection, the linear correlation coefficients of the peak areas of two weak acids were 0.9991 and 0.9985, respectively.

Anions↗
PubMed1999

[The basic study of noninvasive detecting the ischemic/hypoxic cerebral injury].

The cerebrovacular diseases are important causes of mortality and disability in the world, and with the development of science and technology, many mission-oriented basic researches are aimed at the ischemic/hypoxic brain injury. This paper introduces some progress made in our research in this field, which includes: the animal experiment model of brain injury; the technique to efficiently extract evoked potentials from electroencephalogram; and the identification of the characteristic information of brain injury.

Animals↗
PubMed1999

[Study of bacterial adhesion to prosthetic valve materials in vitro].

This article reports a study of the bacterial adhesion to prosthetic valve materials in vitro. The method for assessing the degree of bacterial adhesion to prosthetic valve materials was established primarily. The capacities of staphylococcus aureus(SA), staphylococcus epidermidis(SE), Escherichia Coli(EC) and Pseudomonas aeruginosa(PA) for adhesion to Dacron, Pyrolytic carbon and polytetrofluoroethylene (PTFE) were quantitatively determined by the plate counting and Gamma-ray counting of 125I radiolabeled bacteria in vitro. The results showed that the capacities of four types of bacteria for adhesion to Dacron, Pyrolytic carbon and PTFE coincided with the bacterial-growth curve. The capacities of four bacteria for adhering to Dacron were stronger. The adhesion of SE to Pyrolytic carbon was the strongest. The adhesion of PA Kept up a high level. The capacities of EC and PA for adhering to PTFE were the strongest. The results indicate that the capacities of different types of bacteria for adhesion to the same prosthetic valve material are different, and the capacities of one type of bacteria for adhesion to different materials are also different.

Bacterial Adhesion↗
PubMed1999

[Modification of the surface of prosthetic valve material by LGDP for protection against microbial adhesion].

This study aimed at the surface modification of prosthetic valve materials by means of cold glow discharge plasma. Orthogonal design was adopted to select the optimal scheme by the experiments of the singular factor, such as output power, gas flow rate, treatment time etc. The PEG-200 was introducted to the surface. Grafting a layer of heparin onto the surface; coating a layer of PEG-like onto the surface first, and then the grafting heparin. Comparing the adhesive amounts of staphylococcus epidermidis (SE), the adhesive curves for Dacron, which was treated by the above methods; the last one is the best.

Bacterial Adhesion↗
PubMed1999

[The characteristic wave intervals of exercise ECG influenced by changing of heart rate].

This paper analyzes the characteristic wave intervals of exercise ECG influenced by heart rate changing under exercise test. The most influenced parameter is TP interval, the next is QT interval, and the width of P wave and QRS waves are nearly unchanging. According to the changing characteristic of these waves width mentioned above, we suggest an adaptive adjusting method for ST segment measuring position after the J point, which is of significance to recognizing the characteristic waves and determining the result of exercise test for myocardial ischemia.

Adult↗
PubMed1999

[Sequencing and analysis of a cDNA clone CO111 of Plasmodium falciparum].

AIM: To sequence and analyse a cDNA clone CO111, reacting with immune sera obtained from rabbits immunized with Plasmodium falciparum and one McAb against P. falciparum. METHODS: cDNA clone was amplified by PCR. The PCR product was purified and polished with Klenow enzyme and ligated into the M13mp18 vector (digested by SamI) and then transformed into E. coli JM109. The positive recombinant was screened out by PCR and sequenced by the PRISM Dye Primer Sequencing Kit(ABI). The sequence was analyzed by the program from Geneva University and was compared by GenBank of EMBL. RESULTS: The nucleotide sequence of this cDNA clone contains an open-reading frame of 233 bp, which encodes a predicted polypeptide of 77 amino acid residues. The ratio between A + T and G + C is 3.16. The polypeptide is highly hydrophilic and flexible. Comparison among cDNA of P. falciparum from GenBank of EMBL showed that no sequence identical to this cDNA was found. CONCLUSION: A novel cDNA clone reacted with the antibodies against P. falciparum was isolated.

Amino Acid Sequence↗
PubMed1999

[Determination of T lymphocyte subsets in peripheral blood lymphocytes of patients with chronic tonsillitis].

OBJECTIVE: To observe the cellular immunologic status of patients with chronic tonsillis. METHOD: T lymphocyte subsets in peripheral blood lymphocytes of 60 cases with chronic tonsillis were detected. RESULT: It was found that CD4, CD4/CD8 in chronic tonsillis patients decreased than that in normal control group with statistical significance (P < 0.01). CONCLUSION: This study indicates that the cellular immunologic status in patients with chronic tonsillitis was decreased.

Adolescent↗
PubMed1999

[Report of myringoplasty with interlay method in 53 ears perforation of tympani].

OBJECTIVE: To probe into an eutherapeutic method for the healing tympanic membrane aperture. METHOD: Fifty-three cases of tympamic membrane aperture were treated with myringoplasty of interlay method. The results were compared with that of underlay method of 168 ears in same period. RESULT: The rate of closure of perforation of tympani was 96.2% in interlay method group and 85.7% in underlay method. The hearing recovery of interlay method group was better than underlay method group. Function of Eustachian tube kept good condition in interlay method group. There was no blunting of anterior tympanomeatal angle in the interlay group. CONCLUSION: The interlay method of myringoplasty is an ideal method for healing perforation of tympani.

Adolescent↗
PubMed1999

[The method of wavelet transformation used for extracting the characteristic of the exercise ECG].

This article introduces the basic rationale of wavelet transformation and the algorithm of typical dyadic wavelet transformation with mother wavelet of the first derivative of a Gaussian smoothing function, this wavelet transformation is used to recognize the characteristic parameters of the exercise ECG, it is concluded that this method make significant effects on restricting base line drifting and lessening noisy component in the exercise ECG, it provides a new way to do further research on characteristic recognition of the exercise ECG in the exercise test.

Algorithms↗
PubMed1999

[A multichannel laser Raman spectral detecting system].

A multichannel laser Raman spectral detecting system is described. It consists of Ar+ laser, outer optics, polychrometer and optical multichannel analyzer (OMA II). Raman spectra of CCl4, C6H6 and C6-H12 were detected. Tests showed that the time required to acquire a Raman spectrum with this/multichannel system is greatly reduced, but the integral time per channel can be expanded to 10-50 s in contrast with a conventional single channel Raman spectrometer. When the working temperature of the multichannel detector is dropped to 5 degrees C, the Raman spectra with high signal to noise ratio, high sensitivity and good quality can be obtained. Processing Raman spectral curves with differential software, the Raman lines which are nearly submerged in Rayleigh line can be picked up.

English Abstract↗
PubMed1999

[FTIR and fluorescence emission spectra of sulfonated PS and its ionomers].

The FTIR spectra of sulfonated polystyrene and Zn and La ionomers change with sulfonation degree and the kind of metal ion. With increasing the sulfonation degree, the stretching vibrational strength of -SO3H and -SO3 increases. Because of the interaction of polar group, the FTIR spectra around 1200 cm(-1) or so split. On the other hand, the degree of sulfonation influences somewhat on the intensity and position of fluorescence spectra of sulfonation polystyrene and its ionomers.

English Abstract↗
PubMed1998

Effect of adenophostin A on Ca2+ entry and calcium release-activated calcium current (Icrac) in rat basophilic leukemia cells.

In most non-excitable cells, calcium influx is signaled by depletion of intracellular calcium stores, a process known as capacitative calcium entry. Adenophostin A, a potent activator of the inositol 1, 4,5-trisphosphate receptor, has been reported to activate Ca2+ entry in Xenopus oocytes to a greater extent than expected on the basis of its ability to release calcium stores. In this study, we compared the abilities of adenophostin A and inositol 2,4,5-trisphosphate ((2, 4,5)IP3) to release Ca2+ from intracellular stores, to activate Ca2+ entry, and to activate calcium release-activated calcium current (Icrac) in rat basophilic leukemia cells. Under conditions of low intracellular Ca2+ buffering (0.1 mM BAPTA), adenophostin A-induced Ca2+ release and activation of Icrac could be monitored simultaneously. However, other reagents that would be expected to deplete Ca2+ stores ((2,4,5)IP3, 3-fluoro-inositol 1,4, 5-trisphosphate, thapsigargin, and ionomycin) were unable to activate Icrac under this low Ca2+ buffering condition. Adenophostin A activated Icrac after a significant delay, longer than the delay for Ca2+ release. Thus, adenophostin A activates Icrac as a consequence of release of intracellular Ca2+, rather than directly acting on store-operated channels. The unique ability of adenophostin A to activate Icrac under conditions of low intracellular Ca2+ buffering suggests an additional site of action, perhaps in preventing or reducing rapid Ca2+-dependent inactivation of store-operated Ca2+ channels.

Adenosine↗
PubMed1998

Cytokine and chemokine mRNA expressing cells in muscle tissues of experimental autoimmune myasthenia gravis.

In-situ hybridization with labeled oligonucleotide probes was applied to explore cytokine and chemokine mRNA expression in sections of striated muscle, the target organ in experimental autoimmune myasthenia gravis (EAMG), induced in Lewis rats by immunization with acetylcholine receptor (AChR) and complete Freund's adjuvant (CFA). A transient burst of TNF-alpha, IL-1beta and IL-6 mRNA expressing cells was detected during the early phase of EAMG. This cytokine pattern was related to muscular infiltration of macrophages. Levels of IL-4, IL-10, IFN-gamma, cytolysin and TGF-beta mRNA expressing cells were low and observed mainly during the early phase of EAMG. C-C chemokine RANTES, MCP, MIP-1alpha and MIP-2 mRNA expressing cells were not detected over the course of EAMG. The low and transient expression of cytokines in EAMG muscle tissues suggests that the immune effector responses are unlikely operated by infiltrating cells in muscle. Muscular infiltrations in EAMG are unlikely due to local accumulation of C-C chemokines.

Animals↗
PubMed1998

Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor.

Acetate was produced from whey lactose in batch and fed-batch fermentations using co-immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45-L column reactor, with liquid circulated through a 5-L stirred-tank fermentor. Industrial-grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous-bed reactor volume. The cells isolated from the fibrous-bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate-tolerant strains occurred. This cocultured fermentation process could be used to produce a low-cost acetate deicer from whey permeate and acid whey.

Acetates↗
PubMed1998

Ultraviolet-irradiation-induced apoptosis is mediated via ligand independent activation of tumor necrosis factor receptor 1.

Ultraviolet (UV)-irradiation has been shown to induce jun N-terminal kinase activity via aggregation-mediated activation of tumor necrosis factor receptor 1 (TNFR1) but the role of TNFR1 in mediating UV-induced apoptosis has not been explored. Using p53-null cells, we demonstrate that UV-stimulated ligand independent activation of TNFR1 plays a major role in mediating the apoptotic effects of UV-irradiation. UV-irradiation and TNF alpha acted in a synergistic manner to induce apoptosis. UV-irradiation stimulated the aggregation-mediated activation of TNFR1 which was coupled with activation of caspase 8, the most proximal caspase in TNF alpha signaling pathway. CrmA and the dominant negative versions of FADD, caspase 8 and caspase 10, that block the apoptotic axis of TNFR1 at different levels, also independently inhibited the UV-induced apoptosis. The engagement of the membrane initiated events was specific for UV-irradiation since neither CrmA nor the dominant negative FADD, caspase 8 or caspase 10 blocked the ionizing radiation-induced apoptosis. Cisplatin and melphalan, the UV-mimetic agents known to elicit UV-type DNA damage, also induced apoptosis but differed from UV in that both of the former agents engaged the caspase cascade at a level distal to FADD. Consistent with these findings cisplatin also did not stimulate TNFR1 aggregation. Together these results indicate that DNA damage per se was not sufficient to activate the membrane TNFR1. Based on our results we propose that the plasma membrane initiated events play a predominant role in mediating UV-irradiation-induced apoptosis and that UV-irradiation appears to engage the apoptotic axis of TNFR1 and perhaps those of other membrane death receptors to transduce its apoptotic signals.

Adaptor Proteins, Signal Transducing↗
PubMed1998

No evidence for elevated numbers of mononuclear cells expressing MCP-1 and RANTES mRNA in blood and CSF in multiple sclerosis.

The perivascular accumulation of mononuclear cells (MNC) in brain white matter is critical in the development of active lesions in multiple sclerosis (MS). Chemokines contribute to leukocyte recruitment by increasing the adhesiveness of integrins expressed on leukocytes and by promoting migration through endothelium and extracellular matrix. By using an in situ hybridization technique, it was possible to enumerate blood and CSF MNC expressing mRNA for the two CC chemokines monocyte chemoattractant protein-1 (MCP-1) and RANTES (regulated upon activation, normal T cells, expressed and secreted) in MS patients and controls. No differences in numbers of blood MNC expressing MCP-1 or RANTES could be found in MS patients compared to healthy individuals or patients with acute aseptic meningoencephalitis (AM). High numbers of CSF MNC expressing MCP-1 and RANTES were found in some MS patients, but also in patients with AM. This shows that elevated numbers of MCP-1 and RANTES mRNA expressing CSF MNC are not specific for the inflammatory process in MS. We conclude that there is no evidence for a systemic dysregulation of the CC chemokines MCP-1 and RANTES in MS.

Adult↗