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Biomedical subjects

C Zhang

Publications and source records attributed to C Zhang.

At least 487 records · Page 27Linked to original sources
PubMed1997

Double filtration plasmapheresis for the treatment of rheumatoid arthritis: a study of 21 cases.

The treatment of rheumatoid arthritis remains difficult and often controversial. Plasma exchange has been advocated in some cases. In the present study 71 sessions of double filtration plasmapheresis (DFPP) were performed in 21 patients with rheumatoid arthritis in an average of 3.7 +/- 1.1 sessions per patient within 1-2 weeks. Seven patients had received prednisone, and all the patients had received nonsteroid anti-inflammatory drugs with poor results. Although after the DFPP therapy, only 2 patients were still receiving nonsteroid anti-inflammatory drugs, the function capacities improved in all patients. Five out of 8 positive rheumatoid factors became negative for the group. These results suggest that DFPP could be a regular therapy for rheumatoid arthritis.

Adolescent↗
PubMed1997

Loudness of dynamic stimuli in acoustic and electric hearing.

Traditional loudness models have been based on the average energy and the critical band analysis of steady-state sounds. However, most environmental sounds, including speech, are dynamic stimuli, in which the average level [e.g., the root-mean-square (rms) level] does not account for the large temporal fluctuations. The question addressed here was whether two stimuli of the same rms level but different peak levels would produce an equal loudness sensation. A modern adaptive procedure was used to replicate two classic experiments demonstrating that the sensation of "beats" in a two- or three-tone complex resulted in a louder sensation [E. Zwicker and H. Fastl, Psychoacoustics-Facts and Models (Springer-Verlag, Berlin, 1990)]. Two additional experiments were conducted to study exclusively the effects of the temporal envelope on the loudness sensation of dynamic stimuli. Loudness balance was performed by normal-hearing listeners between a white noise and a sinusoidally amplitude-modulated noise in one experiment, and by cochlear implant listeners between two harmonic stimuli of the same magnitude spectra, but different phase spectra, in the other experiment. The results from both experiments showed that, for two stimuli of the same rms level, the stimulus with greater temporal fluctuations sometimes produced a significantly louder sensation, depending on the temporal frequency and overall stimulus level. In normal-hearing listeners, the louder sensation was produced for the amplitude-modulated stimuli with modulation frequencies lower than 400 Hz, and gradually disappeared above 400 Hz, resulting in a low-pass filtering characteristic which bore some similarity to the temporal modulation transfer function. The extent to which loudness was greater was a nonmonotonic function of level in acoustic hearing and a monotonically increasingly function in electric hearing. These results suggest that the loudness sensation of a dynamic stimulus is not limited to a 100-ms temporal integration process, and may be determined jointly by a compression process in the cochlea and an expansion process in the brain. A level-dependent compression scheme that may better restore normal loudness of dynamic stimuli in hearing aids and cochlear implants is proposed.

Acoustics↗
PubMed1997

Infiltration of eosinophils into the asthmatic airways caused by interleukin 5.

Interleukin (IL)-5 is thought to play an important role in asthmatic bronchial mucosal inflammation and is a potential therapeutic target. To investigate the effect of IL-5 on the infiltration of eosinophils in airway in vivo, we compared eosinophil counts and their activation status in airways without and after the topical instillation of recombinant human IL-5. Eight subjects with mild atopic asthma underwent initial bronchoscopy during which control bronchoalveolar lavage (BAL) fluid as well as bronchial mucosa were obtained, and at the same time, normal saline and IL-5 were administered to two sublobar segments separately. The second bronchoscopy were carried out and samples from challenged sites were taken 24 h later. It was found that the total eosinophils (BMK-13+ cells) and the activated eosinophils (EG2+ cells) in bronchial mucosa, the eosinophil numbers in BAL fluid, as well as eosinophil cationic protein (ECP) in BAL fluid from saline-challenged segments were not different from those in unchallenged segments. However, a significant eosinophilia was observed in bronchial mucosa and BAL fluid from IL-5-challenged sites. Eosinophil activation, as assessed by secretion of ECP, was also increased significantly in bronchial mucosa and BAL fluid. The results strongly suggested that IL-5 is capable of inducing eosinophil infiltration into the asthmatic airways, as well as the activation of infiltrating eosinophils.

Adult↗
PubMed1997

Xenopus Ran-binding protein 1: molecular interactions and effects on nuclear assembly in Xenopus egg extracts.

Ran is a nuclear GTPase implicated in nucleocytoplasmic transport, the maintenance of nuclear structure, mRNA processing, and cell cycle regulation. By two-hybrid interaction in yeast, we have identified a Xenopus homologue of Ran-binding protein 1 (RanBP1). Xenopus RanBP1 interacts specifically with the GTP-bound form of Ran and forms complexes in Xenopus egg extracts with Ran, importin-beta/karyopherin-beta and importin-alpha/karyopherin-alpha, but not p10, p120/RanBP7, RanBP2 or other nucleoporins. These complexes may play roles in the recycling of Ran and importins/karyopherins during nucleocytoplasmic transport. Increased concentrations of RanBP1 stabilise an interaction between Ran and RCC1 in egg extracts, inhibiting the exchange activity of RCC1 towards Ran. Under these conditions, the assembly of nuclei from chromatin is dramatically affected: the nuclei do not assemble a lamina and become very small with homogeneously condensed chromatin. They fail to actively import proteins and do not undergo DNA replication. By field emission in-lens scanning electron microscopy, we show that these nuclei have an intact nuclear envelope containing pore complexes, but the envelope is highly convoluted. However, RanBP1 does not directly inhibit nuclear protein import in assembled nuclei. These results suggest that RCC1 and/or Ran have a function early in nuclear assembly that is disrupted by RanBP1.

Amino Acid Sequence↗
PubMed1997

[The effect of arsenic on reproduction and offspring development of rats].

The effect of arsenic on reproduction and offspring development of Wistar rats was studied. The results demonstrated that the pregnant rate and feeding survival rate in high dose group were lower than these of in the groups of control and low dose. The differences of normal parturition rate and the survival rate in all the groups were not significant. The contents of arsenic in the young rats were increased by the doses of arsenic and the differences were significant. After 10, 20 and 30 days of birth, the weight of offspring in high dose group was lighter than that in the groups of control and low dose. According to the results, arsenic can affect the reproduction of rats and the development of their offspring.

Animals↗
PubMed1997

[Study on measures to increase diagnostic accuracy of FNAC of breast masses].

OBJECTIVE: To study the measures capable of increasing the diagnostic accuracy, reducing misdiagnosis as well as giving a full play to fine needle aspiration cytology(FNAC), in the diagnosis of breast masses, and to standardize the diagnostic report form. METHODS: Totally 1629 cases of FNAC were performed and 444 cases of them were checked with the histological diagnosis. RESULTS: The sensitivity of diagnosis of malignant tumors in 307 cases, the specificity of diagnosis of benign lesions in 137 cases and the overall accuracy of diagnosis were 95.8%, 98.5% and 96.6% respectively. The false negative rate, potential false positive rate and the overall misdiagnostic rate were 4.2%, 1.5% and 3.4% respectively, while no case of false positive diagnosis was found. CONCLUSIONS: We believe that: (1) It is very important to use a fine aspirator, to make smears of high quality, to carry out an integrated working procedure and to put into effect a conscientious check over cytological appearance with histological diagnosis. (2) The diagnositc report form introduced in "the uniform approach to breast fine needle aspiration biopsy" by Bethesda specialists is worthy of reference. (3) FNAC can further play important roles in the diagnosis and treatment of breast masses.

Biopsy, Needle↗
PubMed1997

[A 20-year experience in surgical management of acute necrotizing pancreatitis].

From 1974 to 1994, 243 patients with acute necrotizing pancreatitis (ANP) proved by operation or CT scanning system were treated. The overall survival rate was 70.4%. In 1974-1987, the resection of necrosis was radical and as early as possible, and the main type of operation was subtotal pancreatectomy. The survival rate in this period was 61.3% (49/80). In 1988-1991, the treatment was changed into "individualization" i.e. for sterile pancreatic necrosis, conservative treatment was setected while infected pancreatic necrosis, necrosectomy was performed early. In this period, the survival rate of conservative treatment was 85.7% (6/7) and that of operative treatment 67.1%. The overall survival rate in was 68.5% (63/92). In 1991-1994, we insisted on late operation for the patients with necrosis and comprehensive management for all the patients with ANP. The survival rate of conservative treatment in this period was 100% (11/11) and that of operative treatment 80% (48/60). The overall survival rate was 83.1% (59/71). We conclude that comprehensive management combined with late operation for the patients with necrosis infected is a better strategy for the treatment of ANP.

Adolescent↗
PubMed1997

Clinical and experimental studies on acupuncture treatment of apoplexy at the convalescent stage by consciousness-restoring method.

The consciousness-restoring method and the conventional method of acupuncture were used for treatment of 92 cases of apoplexy at the convalescent stage. They were randomly divided into 2 groups: the consciousness-restoring group (50 cases), and the conventional group (42 cases). The therapeutic results show that the cure rates in the former and latter groups are 43% and 16.67% respectively. The markedly effective and effective rates in the former group are significantly higher than that in the latter group. The experimental results demonstrate that there is remarkable improvement in the majority of criteria of blood rheology, blood lipid, micro-circulation and thrombus formation in vitro, in the former group, and the degree and extent of improvement are markedly better than the latter group.

Acupuncture Therapy↗
PubMed1997

[Surgical removal of submacular choroidal neovascular membranes and the results of follow-up].

OBJECTIVE: To explora the long-term effect of surgical removal of submacular neovascular membranes. METHODS: After pars plana vitrectomy, a small retinotomy technique was used to extract submacular choroidal neovascular membranes in the seven eyes of seven cases. Before and after surgery, the visual acuity, best corrected visual acuity, fundus and fundus fluorescein angiography were examined in all eyes and long-term follow-up was carried out. RESULTS: With more than 1 year follow-up, the submacular choroidal neovascular membranes were not noted in six eyes and recurrent in one eye. After surgery, the visual acuity improved differently in six eyes, two eyes of which increased 5 Snellen lines. Only in one eye did the vision decrease with macular organization, and in one eye a secondary epimacular membrane appeared. CONCLUSION: Most of the eyes have their vision improved after the surgical removal of the submacular neovascular membranes. The visual improvement is related to the extent of retinal pigment epithelium and neurosensory retina damaged by the choroidal neovascular membrane scar, and surgical procedure has also some damaging effects on retinal pigment epithelium and neurosensory retina.

Adult↗
PubMed1997

[Indocyanine green angiography in central serous chorioretinopathy].

OBJECTIVES: To know the results of indocyanine green angiography (ICGA) in central serous chorioretinopathy (CSC) and approach its pathogenetic mechanisms. METHODS: 20 cases of CSC were examined by scanning laser ophthalmoscope to perform blue laser beam examination, fundus fluorescein angiography (FFA) and indocyanine green angiography. RESULTS: (1) The blue laser beam: The elevation lesions of the sensory retinal and retinal pigment epithelial detachment were clearly found. (2) ICGA: In the early phase, choroidal delayed filling (95.0%), choroidal hyper-perfusion (80.0%), choriocapillary dilatation, and in the late phase, hyperfluorescent spots (95.0%), diffuse choroidal hyperfluorescence (77.5%), abnormal fluorescence over vortex vein were found. (3) FFA demonstrated the hyperfluorescence of the choroidal background and the optic disc. CONCLUSIONS: CSC patients have obvious choroidal circulatory disorder and the ICGA is a good method for the study of the pathogenetic mechanisms of the CSC and its therapeutic evaluation.

Adult↗
PubMed1997

[Using Nd-YAG laser to desensitize the hypersensitive dentine in preparing the abutment teeth for removable partial dentures prosthesis].

Patients often suffer from sensitivity and pain while preparing the seats of occlusal rests of clasps on abutment teeth with hypersensitive dentine for removable partial dentures prosthesis. Base Nd-YAG laser desensitization effect by making a hard surface layer in the hypersensitive dentine of the abutment teeth, We use this method to treat the teeth before and after occlusal seats of clasps preparation, 20 patients, more than 30 occlusal seats of clasp rests are completed smoothly without any suffering since 1991. All the patients wear their dentures satisfactorily without afterward side effect. After half one year to four years followed observation all the rests adapt to their seats well without marking wear, We believe that the desensitizing effect of Nd-YAG Laser is effective in preparing occlusal seats for removable partial denture prosthesis.

Adult↗
PubMed1997

[Correlations of T lymphocyte subsets and IL-2, sIL-2R in patients with malignant ovarian tumor].

To study the relation between malignant ovarian tumor (MOT) and cell mediated immunity, the numbers of T lymphocyte subsets and levels of IL-2 and sIL-2R were measured simultaneously in 40 patients with MOT and 30 normal controls (NC), and the correlations between T subsets and IL-2, T subsets and sIL-2R were analyzed. The results were as follows: (1) The numbers of CD3+, CD4+, CD4+/CD8+ and the levels of IL-2 in the patients were lower than those in the NC significantly, and the opposite results were observed about CD8+ and sIL-2R (P < 0.01-0.001); (2) There were positive correlations between CD3+, CD4+, CD4+/CD8+ and IL-2 and there were negative correlations between CD3+, CD4+, CD4+/CD8+ and sIL-2R in MOT group (P < 0.01-0.001). The results suggested that the T lymphocyte immune function in MOT group was decreased. The reduced numbers of CD3+, CD4+, CD4+/CD8+ were related to the decreased levels of IL-2 and the increased levels of sIL-2R. It may be an important factor of incidence and development in MOT.

Adult↗
PubMed1997

[Identification of the anti-rIL-1ra McAb].

Using dot-immuno-blot and Western blotting techniques, we have identified the specificity of anti-rIL-1ra McAbs. The results showed that the anti-rIL-1ra McAb 2E4 specifically reacted with rIL-1ra, from which the recognizing signal of dot-immunoblot was significantly positive (+2) and a single rIL-1ra protein band (20 kd) was clearly recognized by Western blotting. The control results of PcAb recognization have further proved the high sensitivity of Western blotting and high specificity of rIL-1ra McAb 2E4. The successful identification of rIL-1ra McAb 2E4 will be helpful to further understand the biologic effects, especially the pro-inflammatory properties, to study the change of rIL-1ra level during inflammation, and to instruct the clinical use of rIL-1ra.

Animals↗
PubMed1997

[Improved MTT colorimetric assay for serum TNF activity].

The activity of serum tumor necrosis factor(TNF) is known to be related with the mechanism and prognosis of many diseases. The aim of this experiment was to look for an economic and reliable method for assaying the activity of serum TNF. We used the neutrophil solventor 20% SDS-50% DMF instead of the acidity solventor 0.04 mol/l acidified isopropy alcohol and established an improved 3-(4,5-dimethyl thiazoly)2,5-diphenyl-tetrazolium bromide (MTT) colorimetric assay for measuring the amount and function of living cell. We used this improved MTT colorimetric assay for measuring TNF activity of peripheral blood serum of healthy persons. It avoided the deposition of the protein in serum and medium and showed more repeatability, as compared with the conventional MTT colorimetric assay. The results showed: when the activity of target cell(TC)-L929 is > or = 95%, the density of TC is > or = 1 x 10(2)/well and the number of living cells in each well is positively correlated with the OD volume (OD570nm-OD630nm of purple formazan metabolite of MTT solution(r = 0.87, P < 0.01); when the density of TC is 5 x 10(4)/well, the level standard of TNF in each well is negatively correlated with the OD volume (OD570nm-OD630nm)r = 0.79, P < 0.01). Using this method, we measured the TNF activity of 20 healthy persons' peripheral blood serum. The mean +/- s of TNF activity is 20.95 +/- 3.2 IU/ml. This method is dependable, easy-to-do and economic, it has good repeatability within 3-12 hours.

Animals↗
PubMed1997

[Optimization of technical parameters for processing radix Aconiti coreani].

Based on the determination of guanfu A, hypaconitine, and total alkaloids, along with the experiment of acute toxicity of sliced Radix Aconiti Coreani and in compliance with the quality standard stipulated in pharmacopeia-surface features cross section colour and odor of sliced Radix Aconiti Co-reani the technology of processing Radix Aconiti Coreani has been optimized to be steaming the drug for four hours.

Aconitine↗