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Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

At least 91 records · Page 5Linked to original sources
PubMed2001

Solution structure of cytochrome b(5) mutant (E44/48/56A/D60A) and its interaction with cytochrome c.

Using 1617 meaningful NOEs with 188 pseudocontact shifts, a family of 35 conformers of oxidized bovine microsomal cytochrome b5 mutant (E44/48/56A/D60A) has been obtained and is characterized by good resolution (rmsd to the mean structure are 0.047 +/- 0.007 nm and 0.095 +/- 0.008 nm for backbone and heavy atoms, respectively). The solution structure of the mutant, when compared with the X-ray structure of wild-type cytochrome b(5), has no significant changes in the whole folding and secondary structure. The binding between cytochrome b(5) and cytochrome c shows that the association constant of the mutant-cytochrome c complex is much lower than the one for wild-type complex (2.2 x 10(4) M(-1) vs. 5.1 x 10(3) M(-1)). The result suggests the four acidic residues have substantial effects on the formation of the complex between cytochrome b(5) and cytochrome c, and therefore it is concluded reasonably that the electrostatic interaction plays an important role in maintaining the stability and specificity of the complex formed. The competition between the ferricytochrome b(5) mutant and [Cr(oxalate)(3)](3-) for ferricytochrome c shows that site III of cytochrome c, which is a strong binding site to wild-type cytochrome b(5), still binds to the mutant with relatively weaker strength. Our results indicate that certain bonding geometries do occur in the interaction between the present mutant and cytochrome c and these geometries, which should be quite different from the ones of the Salemme and Northrup models.

Amino Acid Sequence↗
PubMed2001

[Study on preparation and properties of moisture permeable polyurethane membrane used for dressings].

A new hydrophilic polyurethane(PU) performed-polymer has been developed with polyethylene glycol(PEG) instead of general polyether. The solution of performed-polymer is poured casting a permeable membrane used for the outer layer of the bilayer dressings. The effects of molecular weigh (Mn) of PEG, the usage of cross-link agents, solvents and water in the solution on the moisture permeation of PU membrane have been studied. It has been shown that the membrane prepared is a porous moisture permeable membrane. The optimum conditions of preparing membrane are: Mn of PEG is 2,000-4,000, the mixture of acetone and N,N-dimethylformamide (DMF) is used as solvents, and the temperature of performance membrane is 50 degrees C-80 degrees C. The moisture permeability of the PU membrane is 49-60 g/m2.h at 35 degrees C, which can meet the requirement of the wound dressings. In addition, the mechanism of the moisture permeation of PU membrane has been discussed.

Bandages↗
PubMed2001

Basaloid squamous cell carcinoma of the esophagus: an immunohistochemical study of 8 cases.

OBJECTIVE: To explore the biological features of basaloid squamous cell carcinoma (BSC) of the esophagus. METHODS: Cytokeratins (CK4, CK18 and CK19), epithelial membrane antigen (EMA), carcino embryo antigen (CEA), alpha-smooth muscle antigen (alpha-SMA), S-100, laminin (LN), collagen IV (Col-IV), neural-specific enolase (NSE), proliferating cell nuclear antigen (PCNA) and p53 antibodies were used to detect the corresponding antigen expression in 8 cases of BSC with ABC immunohistochemical methods. RESULTS: Two kinds of BSC cell components have different responses to the above antibodies. For basaloid cells (BCs), 7 cases were positive for CK19, and were negative for the other 4 epithelial antibodies CK4, CK18, CEA and EMA. BCs of 4 cases were positive to the muscular antibodies alpha-SMA and S-100, and the hyaline degeneration in the tumor nests was positive for LN and Col-IV. BCs had a high index of PCNA, with an average level of 54%. For squamous cells (SCs), 7 cases were positive for the epithelial antigen CK4, CEA and EMA, but were negative for CK19, alpha-SMA and S-100. The index of PCNA of SC was low, with an average level of 25%. CONCLUSION: BSC of the esophagus is a high-malignancy tumor which is of multi-oriented differentiation. BCs represent basal cells which have the tendency of myoepithelial differentiation and have strong proliferation ability, whereas SCs represent typical squamous cell differentiation.

Carcinoembryonic Antigen↗
PubMed2001

Bimodal effects of 1R,2R-diaminocyclohexane(trans-diacetato)(dichloro)platinum(IV) on cell cycle checkpoints.

1R,2R-Diaminocyclohexane(trans-diacetato)(dichloro)-platinum(IV) (DACH-acetato-Pt) is a novel platinum-based agent that is highly effective against cisplatin-resistant ovarian tumor cells. To probe its cellular mechanism, the effects of DACH-acetato-Pt (0-6.4 microM) on cell cycle checkpoints were examined using the ovarian cancer A2780 cell line as the model system. We found that DACH-acetato-Pt at > or =0.2 microM dramatically inhibited cell growth and induced cell death. At concentrations < or =0.6 microM (low effective concentrations), DACH-acetato-Pt specifically induced G(1) phase arrest by selectively inhibiting cyclin-dependent kinase 4 (Cdk4) and Cdk2 activities. The Cdc2 activity, which regulates G(2)-M phase progression, was unaffected by the drug at these concentrations. At concentrations >0.6 microM (high effective concentrations), DACH-acetato-Pt first transiently inhibited S-phase progression and then blocked cell cycle progression at both G(1) and G(2) phases. These cell cycle effects were associated with sequential inhibitions of Cdk2/cyclin A activity, Cdk4 and Cdk2 activities, and Cdc2 kinase activity. Following the cell cycle effects, both the low and high effective concentrations of DACH-acetato-Pt induced cell death through apoptosis. These results indicate that DACH-acetato-Pt activates multiple cell cycle checkpoints in a bimodal manner and suggest that the cell cycle effects demonstrated in these studies may be linked to its ability to induce apoptosis.

Antineoplastic Agents↗
PubMed2001

Epitope mapping on Wegener's granulomatosis autoantigen proteinase 3.

OBJECTIVE: To map the epitopes on Wegener's granulomatosis autoantigen proteinase 3. METHODS: Antigenicity of proteinase 3 was studied with Western blot analysis in which proteinase 3 was prepared under reducing and non-reducing conditions. Two anti-proteinase 3 monoclonal antibodies, HZ1F12 and HZ1H3, were used to inhibit each other and to inhibit 22 anti-proteinase 3 positive sera from patients with Wegener's granulomatosis in competitive inhibition enzyme-linked immunosorbent assays (ELISA) and Western blot analysis. RESULTS: All monoclonal antibodies and patient sera recognized proteinase 3 under non-reducing conditions in Western blot analysis. ZH1F12 was inhibited 74% by HZ1H3. 10/22 (46%) sera were completely or partially inhibited by HZ1F12; 9/22 (41%) sera were partially inhibited by HZ1H3; and 6/22 (27%) were inhibited by both monoclonal antibodies. In inhibition Western blot analysis, the binding of patient sera to proteinase 3 could be inhibited by HZ1F12. CONCLUSIONS: The epitopes of Wegener's granulomatosis autoantigen were conformational. Anti-proteinase 3 monoclonal HZ1F12 and HZ1H3 recognized similar or overlapping epitopes on the proteinase 3 molecule. Epitopes of proteinase 3 recognized by anti-proteinase 3 positive sera were not restricted.

Animals↗
PubMed2001

Gene transfer and expression in rat anastomotic artery in vivo using adenoviral vector.

OBJECTIVE: To observe the efficiency and time course of gene expression and the safety of adenoviral vector mediated gene transfer in vivo. METHODS: After soaking soluble stents in a high concentration of glucose solution containing Adv5-CMV (cytomegalovirus) (control group) or Adv5-CMV/LacZ (treatment group) for 30 minutes, the stents were inserted into the lumina of cut rat carotid arteries and end-to-end anastomoses of the cut carotid were performed with standard microvascular surgical techniques. On days 2, 7, 14, 28, 60 and 90 after gene transfer, anastomotic arteries of the two groups were observed. On days 7 and 14, the ascending aortas, hearts, brains, livers, lungs, spleens and kidneys of the treatment group were observed. All samples were analyzed for the presence of beta-galactosidase activity and histochemical staining. RESULTS: beta-galactosidase activity was not detected in the carotid arteries of the control group and organs not directly exposed to adenoviral vector of the treatment group. The amount of beta-galactosidase activity (x 10(-3) U/g tissue) in the treatment group on the 2nd, 7th, 14th, 28th, 60th and 90th day after gene transfer was 3.87, 11.38, 9.8, 6.43, 3.18 and 2.43, respectively. Microscopic examination of sections from vessels of the control group and from the aortas, hearts, brains, livers, lungs, spleens or kidneys of the treatment group revealed no X-gal staining. Microscopic examination of carotid arteries of the treatment group revealed blue-staining in all anastomotic arteries and in all layers of the arterial wall observed on days 7 and 14 after gene transfer. CONCLUSION: Adenoviral vector can effectively infect blood vessels in vivo. After adenoviral vector mediated direct gene transfer into anastomotic rat carotid arteries, recombinant gene expression began on day 2, peaked between days 7 and 14, prominently declined after day 28, and persisted at low levels more than three months. A recombinant gene could be delivered to a specific site by direct gene transfer in vivo by adenoviral vector infection.

Adenoviridae↗
PubMed2001

[Extent of lymphadenectomy in stage I-IIIA non-small cell lung cancer: a randomized clinical trial].

OBJECTIVE: To study the role of radical systematic mediastinal lymphadenectomy for non-small cell lung cancer (NSCLC). METHODS: All 504 operable eligible cases with NSCLC were randomly divided to a radical lymphadenectomy (RL) group and a conventional lymph node dissection group (control) treated between Aug. 1989 and Dec. 1995. For patients postoperatively eligible, thirteen parameters (operation type, pathological type and grade, tumor size, total number of dissected lymph nodes, number of metastatic lymph nodes, metastasis ratio of lymph nodes, postoperative TNM staging, adjuvant therapy, recurrence or metastasis, morbidity, survival and life quality) were evaluated. The end point of follow-up was Dec. 31, 1998. Lost follow-up rate was 1.9%. The results were analyzed with soft were SPSS7.5. The cumulative survival was calculated by the Kaplan-Meier method and compared by the log rank test. The prognostic factors were analyzed by the Cox model. RESULTS: There were 320 cases, 160 cases in each group, who entered the study. The mean numbers of dissected lymph nodes was 9.49 in the RL group and 3.63 in the control group. For stage I NSCLC patients, the 1,3,5,9-year survival rate was 91.8%, 86.9%, 81.4%, 74.2% respectively in the RL group and 88.7%, 72.5%, 58.5%, 52.1% respectively in the control group (P < 0.014). However, no statistically significant difference in survival rates between RL and control groups of patients with stage II and IIIA NSCLC. The postoperative TNM staging, metastasis ratio of lymph nodes, extent of lymphadenectomy were the factors influencing long term survival upon multivariable analysis. CONCLUSION: Classical lobectomy or pneumonectomy with radical systematic mediastinal lymphadenectomy is the surgical treatment of choice for NSCLC.

Adult↗
PubMed2001

[Diagnosis and treatment of 31 patients with splenic tumors].

OBJECTIVE: Splenic tumor, a rare disease, is scarcely mentioned in the literature. Here, we wish to present a clinical study on 31 such patients treated in the PLA General Hospital with emphasis on diagnosis and treatment. METHODS: Thirty-one splenic tumor patients were treated from January 1990 to December 2000. The clinical manifestations and image characteristics of splenic tumor, diagnosis and treatment were analysed. RESULTS: Male 19, female 12. Their ages ranged from 13 to 80 years with an average of 56. The symptoms and signs were non-specific. All patients were first diagnosed by beta-ultrasonography to have single or multiple space-occupying lesions. Then, 19 patients received CT and 7 MRI scans. The diagnosis of seven patients suffering from splenic cysts were initially made definite by beta-ultrasonography among whom the lesions of 6 were confirmed by operation and pathology. The diagnosis of 9 patients with metastatic tumor was ascertained by combined imaging and clinical history. Finally, the lesions were confirmed by operation and pathology. Fifteen patients with primary splenic tumor were found to have primary space-occupying lesion by imaging: Except one patient who was diagnosed to have splenic lymphoma and not operated, all the other 14 patients underwent splenectomy with their lesions confirmed by pathology. Altogether, 25 of these 31 patients were treated by splenectomy with uneventful recovery without any operative mortality. Final pathologic examination disclosed that 20(65%) of 31 lesions were benign. CONCLUSION: Clinical history and imaging scans are important in the diagnosis of splenic tumors. The differentiation of benignity and malignancy is difficult before operation. Surgery is satisfactory in treating splenic tumors.

Adolescent↗
PubMed2001

[Evaluation the pathological diagnostic values of koilocyte in condyloma acuminatum].

OBJECTIVE: To evaluate the histological diagnostic values of koilocyte in histopathologic diagnosis of condyloma acuminatum. METHODS: Koilocyte was served as diagnostic criteria to scan 2 063 biopsies and compared the results with "goldan standard" of histopathologic diagnosis of condyloma acuminatum. RESULTS: Using koilocyte as diagnostic standard to diagnose condyloma acuminatum, the sensitivity and specificity were 77.93% and 95.26%, with positive predictive value 97.25%, negative predictive value 66.70%, positive likelihood rate 81.81, negative likelihood rate 23.17, under diagnostic rate 22.07%, misdiagnostic rate 4.74%. CONCLUSION: The koilocyte was proved to be one of classical histopathological morphologic features of human papillomavirus infection and other virus infection which served one of the most important histopathological markers for diagnosis of condyloma acuminatum, but not the only one.

Biopsy↗
PubMed2001

[Acoustic analysis in patients with trauma to unilateral cricoarytenoid joint by computer technique].

OBJECTIVE: To investigate the acoustic characteristics of unilateral cricoarytenoid joint trauma and evaluate the effect of acoustic analysis technique on the diagnosis and treatment of this disease. METHOD: The voice signals of sustained vowel [a] were measured using a micro-computer with Dr. Speech software in 50 healthy adults and 30 patients with unilateral cricoarytenoid joint trauma. The acoustic parameters (jitter, shimmer and NNE) and spectrographic characteristics (harmonic waves, formants and noise) were analyzed. The acoustic changes before and after the treatment of arytenoid motion were observed and compared. RESULT: All acoustic parameters were significantly increased in trauma of unilateral cricoarytenoid joint. The pathologic spectrograph showed decrease or loss of harmonic waves and formants, and increase of noise, in middle and high frequencies. There was a relationship between NNE and the position of the vocal cord. After the treatment of arytenoid motion, 33% patients were cured and had normal acoustic parameters and spectrograph. 47% were improved with reduced parameters and improved spectrograph. The acoustics in 20% cases didn't change at all after treatment. The acoustic parameters were significantly decreased after the treatment of arytenoid motion. CONCLUSION: The present study suggested that the acoustic parameters may estimating the degrees of voice lesion as objective standards and NNE may judge the degree of glottic closure. Both acoustic parameters and spectrograph are of value in the diagnosis, treatment effect and prognosis observation to cricoarytenoid joint trauma.

Adolescent↗
PubMed2001

[Study of the reconstruction methods after vertical partial laryngectomy for glottic carcinoma of the larynx].

OBJECTIVE: To study the reconstruction methods after vertical partial laryngectomy for glottic carcinoma of the larynx. METHOD: 58 cases with glottic carcinoma of the larynx were treated with vertical partial laryngectomy or extended vertical partial laryngectomy. The clinical materials of these cases were retrospectively studied. RESULT: The total decannulation rate was 93.1% and the 3- and 5-year survival rates were 87.2% and 80.5% respectively. The voice was socially acceptable in 93.1%(54/58) of the patients. Aspiration was only 3. All resumed mouth-food-taking. CONCLUSION: The reconstruction methods after vertical partial laryngectomy were mainly decided by the extent of the laryngeal defect. If the laryngeal defect of the framework was small, the pedicle muscular flap was the best reconstruction method in comparison with other reconstruction methods. If the laryngeal defect of the framework was too big, allograft nasal septal cartilage or epiglottic laryngoplasty should be performed.

Aged↗
PubMed2001

[Eight cases of rhabdomyosarcoma in head and neck].

OBJECTIVE: To improve the clinical diagnosis and treatment level of rhabdomyosarcoma in head and neck. METHOD: It was based on the documents that 8 cases of rhabdomyosarcoma in head and neck had been diagnosed by pathological diagnosis. RESULT: The 8 cases were treated by operation. Among 8 patients, 5 took radiotherapy after operation. 1 took chemotherapy after operation. We kept in touch with 7 patients, the survival rate of 5 years was 57.1% (4/7). CONCLUSION: We must pay attention to the painful or painless phyma in the otolaryngology and head and neck. It has the possibility of being rhabdomyosarcoma. We diagnose the rhabdomyosarcoma through biopsy and immuohistochemistry and with the references from the examination of CT, MR. In order to improve the survival rate of patients of rhabdomyosarcoma, we should use the comprehensive treatment, including operation, radiotherapy, and chemotherapy.

Adolescent↗
PubMed2001

[Diagnostic value of computer-based endoscopy system].

OBJECTIVE: To assess the roles of computer-based endoscopy system as a clinical tool in evaluation of laryngeal disorder. METHOD: An extensive research of 100 patients under stroboscopy examination with acoustic and EGG signal was made, and a number of quantitative information, such as contact quotient, glottal noise and glottal area changes, was examined. RESULT: Quantitative information contributes significant diagnostic information in 14 cases, resulted in avoidance of surgery in 6 cases and 8 cases referred to surgery instead of voice and medical therapy. CONCLUSION: Acoustic and EGG measures should be used as substantially complements of endoscopy examination in the routine clinical examination.

Glottis↗
PubMed2001

[Research progress in physiological functions of selenoenzyme and other selenocompounds].

Selenium (Se) is an essential trace element for animals. Selenocysteine (Sec), the 21st aminoacid, is a component of selenoproteins and has been founded in the active center of selenoenzymes. The functions of Se within the body have been primarily shown in the forms of selenoproteins, especially selenoenzymes. Incorporation of selenocysteine occurs on the basis of genetic expression and Se is the only trace element under direct genetic control. Recently, findings have shown that Se and selenocompounds conducted many other potential functions such as protection against inflammatory factors, inhibition of protein kinase C (PKC), stimulation of MAP kinase (mitogen activated protein kinase/myelin basic protein kinase) and S6 kinase (ribosomal S6 protein kinase), regulation of the immune system and interaction with other elements and vitamins etc, suggesting that the roles of Se in human health may be more diverse than previously suspected.

Humans↗
PubMed2001

[Investigation on genotype constitution of different Plasmodium vivax isolates and its geographical distribution in China].

OBJECTIVE: To investigate the population constitution and geographical distribution of Plasmodium vivax in China using molecular technique. METHODS: Blood-spot filter paper samples with related epidemiological data were collected from vivax malaria patients living in malarious area of 10 provinces (autonomous region) in China. Semi-nested- or nested-allelic-specific PCR genotyping method was used to identify CSP genotypes, families and types of Plasmodium vivax of each isolate from these patients. RESULTS: Of 384 field isolates of Plasmodium vivax, 258 temperate zone family strains were identified, including 14 allelic variant genotypes spreading among 10 sampling provinces; allelic variants sized less than 731 bp were only seen in 5 provinces in southern China; 79 tropical zone family strains including 5 genotypes were also distributed in 5 provinces of southern China south to 25 degrees N. lat; and 14 PV Type-2 strains including 2 genotypes were found in some areas of Hainan and Yunnan Provinces. In addition, 33 isolates from genotype-mixed infections were revealed. CONCLUSION: At present, area north to 25 degrees N. lat. of the country is the sole area prevalent for Plasmodium vivax family strains of temperate zone; there is overlapping distribution of P. v. of temperate zone family and tropical zone family of this parasite in the southern China south to 25 degrees N. lat; where the most complex isolate constitution is in Yunnan and Hainan Provinces, and PV Type-2 strains have been found in some areas of the two provinces. Besides, there were 2 groups of genotype with distinct geographic distribution feature within the temperate zone family.

Animals↗
PubMed2001

[Study on antitumor effect and mechanism of aloe polysaccharides].

OBJECTIVE: To study the antitumor activity and mechanism of aloe polysaccharides (AP). METHODS: AP was administered i.p. or i.v. to Sarcoma 180(S180) bearing mice or Hepatoma22(H22) bearing mice solely or combining with CTX, FU and ADM respectively. 10 days later, for S180 mice, the blood was analyzed, the tumor was peeled off and weighed, and the spleen index, thymus index was calculated. For H22 bearing mice, the survival rate was observed or the IL-2, TNF content in serum was tested. RESULTS: 25 mg/kg.d or 50 mg/kg.d AP group could evidently reduce the tumor weight of S180 bearing mice and prolong the survival time of H22 bearing mice. AP also could improve the antitumor effects of CTX, ADM, FU, and lessen the chemotherapy side-effects. Furthermore, AP could improve the level of IL-2, TNF in the serum of mice bearing S180 or H22. CONCLUSION: AP has the effects of antitumor, enhancing the antitumor activity of chemotherapy drugs and lessening their side-effects. This effect was possibly derived from inducing IL-2 and TNF producing in body and improving the immunity activity.

Aloe↗
PubMed2001

[Study on vibration mode of different phonatory source and compensation after partial laryngectomy].

OBJECTIVE: To investigate the nature of pathological voice production and compensatory mechanism after partial laryngectomy. METHODS: Vocal function of 93 cases following partial laryngectomy (28 cases of horizontal partial laryngectomy, 35 vertical partial laryngectomy, 30 horizontal-vertical partial laryngectomy) were examined by acoustic analysis, aerodynamic analysis and videostroboscopic examination. RESULTS: Horizontal supraglottic laryngectomy(HL) resulted in slight dysphonia after operation. The cover of vocal fold was hypertrophic and edematous. Mucosa wave was increased. Acoustic analysis showed significant difference between normal and horizontal laryngectomy groups(P < 0.05). Vertical laryngectomy(VL) resulted in moderate-severe dysphonia. Acoustic analysis was significantly worse in VL than in normal group(P < 0.01). The nonglottic phonatory source was the contralateral ventricular fold or contralateral vestibular mucosa (arytenoid mucosa, root mucosa of glottis) to approximate the reconstructed flap. It was noted that contralateral vocal fold did not participate in vibration. Horizontal-vertical partial laryngectomy (HVL) resulted in moderate-severe dysphonia. Acoustic analysis of HVL was significantly worse than that of normal phonation(P < 0.01). The site of compensatory mucosa vibration upon phonation was the contralateral vocal fold or contralateral hypertrophic arytenoid mucosa. The thinner the flap, the better the vocal quality was. Vocal quality of VL was worse than that of HVL in regard to shimmer, jitter, normalized noise energy, maximal phonation time and harmonic-noise ratio, but there was no significant difference between them. CONCLUSIONS: Partial laryngectomy has different vibrating compensatory modes: Voice function of horizontal partial laryngectomy was the best as it preserved the normal vibration mode; vertical partial laryngectomy was the worst with the nonglottic vibrating source of reconstructed flap-ventricular fold. The reconstructed flap, ventricular fold, mucosa of epiglottis and arytenoid take predominantly part in neoglottal vibration. The situation, volume and pliability characteristic of reconstructed flap was also important to vocal quality.

Aged↗