Biomedical subjects
Publications and source records attributed to M Dong.
OBJECTIVE: To research the clinical characters of the hoarseness in children. METHOD: 79 cases are analysed retrospectively. RESULT AND CONCLUSION: Age for this disease is usually 3 years old. People with irritable character are more easy to get it. Vocal nodule is the main cause to chronic hoarseness in children. Conservative treatment is important.
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A large number of multidrug resistance (MDR) modulators, termed chemosensitizers, have been identified from a variety of chemicals, but most have been proven to be clinically toxic. Low concentrations of the pleuromutilin-derived semi-synthetic antibiotic tiamulin (0.1 to 10 microM) sensitized the three highly resistant P-glycoprotein (Pgp)-overexpressing tumor cell lines P388 (murine lymphoid leukemia), AS30-D (rat hepatoma), CEM (human lymphoblastic leukemia), and the barely resistant AS30-D/S cell lines to several MDR-related anticancer drugs. Flow cytometric analysis showed that tiamulin significantly increased the intracellular accumulation of daunomycin. When compared to reference modulating agents such as verapamil and cyclosporin A, tiamulin proved to be 1.1 to 8.3 times more efficient in sensitizing the resistant cell lines. Moreover, when given i.p. (1.6 microg/mg body weight), tiamulin increased the survival rate of adriamycin-treated mice bearing the P388/ADR25 tumor line by 29%. In the presence of an anticancer drug, tiamulin inhibited both ATPase and drug transport activities of Pgp in plasma membranes from tumor cells. Tiamulin is thus a potent chemosensitizer that antagonizes the Pgp-mediated chemoresistance in many tumor cell lines expressing the MDR phenotype at different levels and displays no toxic effects on contractile tissues at active doses, therefore providing the promise for potential clinical applications.
Changes in neutralizing antibody (NA) titers in stored sera collected over 5 years from 10 participants in the Multicenter AIDS Cohort Study (MACS) were evaluated. The participants were HIV-1 infected on enrollment in the MACS, and remained AIDS free during the 5-year study interval. Seven viruses derived from molecular clones were used in NA assays; five of the viruses were T tropic (NL4-3, ALA1, NY5, SF2, and Z2Z6) and two were M tropic [AD8 and NL(SF162)]. In addition, pseudoviruses (PVs) were constructed that expressed envelope genes from NL4-3, ALA1, AD8, and SF162 and from primary viruses from two MACS participants (PV-9 and PV-10). There was significant correlation between NA titers obtained in four of five virus/PV comparisons, while the SF162 PV was more sensitive to NA than the corresponding virus. Comparable changes in NA titers were detected using viruses and PVs. Fourfold or greater increases in NA titers were noted in each of the participants, involving recognition of one to five of the nine strains tested. In some patients these NA titer changes appeared as discrete episodes of immune responses, while in others there may have been either multiple episodes or continuous evolution of the NA responses. The data indicate that changes in NA specificity occur during HIV-1 infection, which may result from the occurrence of neutralization escape mutation. The use of PVs for the study of phenotypic characteristics of envelope glycoproteins should facilitate the study of neutralization escape mutation in HIV-1 infection.
P-glycoprotein (Pgp) is a plasma membrane protein known as an ATP-dependent drug-efflux pump that confers multidrug resistance to tumor cells. Structural analysis of Pgp was investigated by circular dichroism (CD) for the first time and in combination with amino acid sequence analysis. CD of highly purified Pgp from human, rat and murine Pgp-overexpressing drug resistant cells revealed slight variations in the spectral shape when recorded in the presence of dodecyl maltoside (DM). These species-dependent variations in CD shapes resulted from the interaction of the oligosaccharidic part with the protein core since they were abolished either in the presence of sodium dodecyl sulfate (SDS) or after deglycosylation, the latter not altering the Pgp ATP-dependent drug transport activity. Whatever the level of Pgp glycosylation and the detergent used (SDS or DM), the content in secondary structure deduced from deconvolution of CD spectra is almost the same for the three sources of Pgp and estimated to 43% alpha-helix, 16% beta-sheet, 15% beta-turn and 26% of other structures. These data, which constitute the first report of Pgp structure analysis by circular dichroism, are consistent with the 48% alpha-helix and 16% beta-sheets global contents predicted by using recently reported efficient secondary structure prediction methods. This consistency reinforces the reliability of the probable nature and localization of predicted Pgp secondary structure elements. This provides a good framework for precise 3D structure modeling of Pgp by homology with proteins of known 3D structure, as it is illustrated here for the A motifs of the ATP-binding domains of Pgp.
Previous studies reported different frequencies of p53 expression between Japanese and Americans or Europeans. The present study was designed to clarify whether there is a significant difference in p53 expression and its clinical implications between Chinese and Japanese patients with primary invasive ductal carcinoma (IDC) of the pancreas. p53 expression was studied in 39 Chinese and 47 Japanese patients, and immunostaining with the SAB method was performed using anti-p53 monoclonal antibody (DO-1) in formalin-fixed and paraffin-embedded specimens. Clinical data were analyzed according to the International Union Against Cancer classification. p53 expression was seen in 71.8% of Chinese and in 48.9% of Japanese patients with IDCs of the pancreas (p < 0.05). The Chinese patients were significantly younger than the Japanese ones (p < 0.05), but there were no significant correlations between p53 immunoreactivity and age, gender, stage, and histopathological grade in separate analyses of the Chinese and Japanese patients. A comparison between them showed that in patients younger than 55 and 65 years old, the incidence of p53 expression was markedly lower in Japanese than in Chinese (p < 0.05). In Japanese patients, those with a p53-positive pancreatic cancer had a significantly lower survival rate than those with a p53-negative tumor, but there was no correlation between p53 expression and the prognosis of Chinese patients. The frequency of p53 expression in IDC of the pancreas is higher in Chinese than in Japanese patients, and the effect of p53 expression on prognosis is different between Chinese and Japanese patients.
Using citric-LSAB-microwave immunohistochemical technique, the expression of c-myc was studied in different regions of larynx including laryngeal squamous cell carcinoma (LSCC), border area, adjacent mucosa which was 0.5, 1.0, 1.5 and 2.0 cm away from cancer 30 cases and four cases of normal laryngeal mucosa. The results showed that over-expression of c-myc in LSCC was found in 29 of 30 (96.7%), which was higher than that in normal laryngeal mucosa (P < 0.01). A significant different expression of c-myc can be seen at the regions of 2.0 and 1.5 cm distant from the tumor (P < 0.05). The expression of c-myc increased as tissue progressed in sequence from normal mucosa, adjacent mucosa to carcinoma. The c-myc expression did not correlate with site of tumor, stage and histological grade (P > 0.05). The results indicate that over-expression of c-myc is involved in genesis of LSCC, and may be an early event in the development of human squamous-cell carcinoma of the larynx. The tissue adjacent to the tumor may have a potential malignancy.
By using intravital microscopy measurement with image processing system, continuous diameter changes were measured by self-tracking with computer, the present study is to investigate specific property of vasomotion in cochlear microvessels and its responsibility to the endothelium-derived relaxation factor (EDRF/NO). The results demonstrated that the vasomotion of cochlear arteriole existed in normal condition in a small pattern. It was found that the vasomotion was significantly enhanced after administration of L-arginine(which is donor of EDRF/NO), and L-arginine induces a sequence of changes in cochlear blood flow. There were significant statistic difference before and after the drug administration. The conclusion suggest that EDRF/NO play an important role in the increase of blood flow by improvement of vasomotion.
Dual task test (light target tracking and visual-motor reaction of visual oddball mode) and pursuit aiming test were done in 17 male healthy subjects after 30min exposure to whole-body vibrations of 20 Hz 0.15 gz or 20 Hz 0.3 gz. Mean accuracy rate of visual-motor reaction and target stimulus reaction accuracy rate after 0.3 gz vibration were significantly lower than those of control group (P < 0.05), while after 0.15 gz vibration, the changes were not significant. Comparing with control group, the total number of right and wrong pointing, pointing speed in pursuit aiming test were significantly lower (P < 0.05) after vibration. However, light target tracking error, mean reaction time of visual-motor reaction and pointing accuracy rate of pursuit aiming test had no significant change after exposure to any kind of the vibrations. It may be concluded that some kinds of effect on human tracking performance and visual-motor reaction were observed after exposure to whole-body vibration.
The efficiency of multistage evaluation scale (MES) based on the fuzzy set theory as used in subjective assessment of mental workload was studied, and the results were compared with those of tracking performance and category scale (CS). It was found that error (ER) significantly increased when task became more difficult (P < 0.01) and the scalings of MES and CS also increased, but that of MES was significantly different in tasks of all the three difficulties (P<0.01) while those of CS was significant only between tasks 1 and 3 as well as tasks 2 and 3 (P <0.01), but not between tasks 1 and 2. These show that the result of MES is more agreeable with that of ER. So it might be a better subjective assessment measure of mental workload.
With different task load levels and input modality formats, P3 wave of event related brain potential (ER-P) were recorded and analyzed in eighteen healthy young man performing six dual tasks. The dual task was made up of visual tracking primary task (T) and Sternberg additional task (S) or Oddball additional task (O) (TS and TO). Its difficulty was controlled by changing the velocity and dimension of movement of target in primary task. The results showed that P3 latency (LAT) prolonged when the primary task was more difficult and its changes of amplitude(AMP) depended on the input modality formats of primary task and additional task. AMP of TO dual task with different formats decreased when the primary task was more difficult and that of TS with same formats increased. It suggests that task load level and input modality format may influent P3 wave of event related brain potential.
OBJECTIVE: To improve the surgical resection rate of complicated retroperitoneal tumors which depends on handling of celiac major blood vessel. METHODS: 219 retroperitoneal tumours were resected from 1990 to 1997. Eleven of them were resected in combination of resections and reconstructions of inferior vena cava (IVC) and renal veins (RV). IVC below RV was resected in 5 cases, IVC below liver with resections of right kidney in 3 cases, IVC above RV in 1 case, major partial resections of left RV with anastomosis to left ovarian vein in 2 cases, and 1 of them with IVC resection. RESULTS: Follow-up showed transient bilateral lower limbs edema in 3 cases. The values of blood urea nitrogen and creatinine were normal after operations, no changes were found in the kidneys under ultrasonic examination. CONCLUSION: As the left renal vein has many branches and constant anastomotic branches that connect with peripheral veins, it can be ligated proximally; and it even can be resected when at least one of its branches (routinely lift sexual gland vein) can be kept to maintain the blood circulation. Reconstruction of IVC and RV is usually not necessary after the resection of IVC, unless the bilateral renal veins were obstructed.
OBJECTIVE: To investigate specific property of vasomotion in cochlear microvessels and its response to the endothelium-derived relaxation factor (EDRF). METHODS: The dynamic changes of cochlea microvessels were observed using intravital microscopy and measured by the microcirculatory image processing system. The frequency and amplitude of vasomotion were analyzed with fast Fourier transform (FFT) according to the diameter changes. RESULTS: The vasomotion of cochlear arteriole with a small amplitude existed in normal condition. The diameter changed from (10.41 +/- 3.03) microns to (12.29 +/- 1.9) microns with a mean value of (11.2 +/- 2.7) microns. The specific property of vasomotion was characterized by a frequency (0.021 +/- 0.002) Hz and amplitude of (0.37 +/- 0.11) micron. The contraction index was determined as 0.42 +/- 0.17. The vasomotion was significantly enhanced after the administration of EDRF. CONCLUSION: The vasomotion existed in the cochlea and EDRF can increase the cochlear blood flow by improving the vasomotion.
Up to now, removal of sodium dodecyl sulfate (SDS) from proteins in terms of restoration of their activity was an unsolved problem. A general procedure using ceramic hydroxyapatite (HAP) chromatography was developed for the complete removal of SDS bound to soluble or membrane proteins. This procedure involves (i) the binding of the SDS-protein complexes onto the ceramic hydroxyapatite column, (ii) extensive washing of bound proteins with phosphate buffer containing a mild detergent to exchange SDS, (iii) elution of the retained protein by increasing the phosphate concentration. Using this approach, complete exchange of [35S]SDS into a nonionic detergent such as dodecyl maltoside was achieved with a 90-100% protein recovery. The efficiency of protein-bound SDS removal is very likely due to the combined effect of phosphate ions and the hydrophobic tail of nonionic detergent: acting together, they are able to displace SDS molecules from their protein-binding sites. The advantages of this HAP-mediated SDS removal method include high efficiency, rapidity, simplicity and general applicability to a wide variety of detergents and soluble or membrane proteins. Of utmost importance, SDS-treated P-glycoprotein, glutamate dehydrogenase, and lysozyme fully recovered their enzymatic activities after HAP chromatography, including lysozyme electroeluted from SDS-polyacrylamide gel electrophoresis. This demonstrates that reactivation of SDS-treated protein can be achieved, provided that SDS is completely removed under mild conditions.
The structural investigation of G protein-coupled receptors has been hindered by the lack of techniques to effectively resolve the hydrophobic peptides obtained by chemical or proteolytic cleavage, as well as the minute amounts of protein typically isolated. We have developed a capillary electrophoresis method for efficient separation of hydrophobic peptides using a cyanogen bromide digest of bacteriorhodopsin as a model for these clinically important membrane proteins. This procedure includes (i) solubilization of the protein digest in acetic acid; and (ii) electrophoresis using an acetic acid-based buffer system augmented by acetonitrile and hexane sulfonic acid, in a Polybrene-coated fused silica capillary. The potential for detection sensitivity to be increased at least 100-fold by use of on-line solid-phase extraction on C18-silica is shown. This approach is potentially useful for peptide fingerprinting of sparse and extremely hydrophobic membrane receptors.
Eighty two cattle naturally infected with haemosporidians were treated with total alkaloid hydrochloride of Peganum harmale L. (0.5 mg/kg/day). Fifty eight cases with Theileria sergenti showed a cure rate of 86%; thirteen cases with Theileria annulata showed a cure rate of 85%; eight cattle infected with Babesia bigemina showed a cure rate of 88% and three cases of Anaplasma marginale were completely cured. The results suggested that the curative effect of total alkaloid of P. harmale was better than that of diminazene aceturate and produced minimal side effects. The alkaloid could also be administered to pregnant animals. It was concluded that the total alkaloid of P. harmale showed a marked effect as a treatment for haemosporidican infections in cattle.
UNLABELLED: In order to evaluate the role of human papillomavirus (HPV) infection and p53 protein expression in laryngeal squamous cell carcinoma (LSCC), the in situ hybridization and the labelled streptavidin biotin (LSAB) immunohistochemical method were used to detect the presence of HPV genomes 6B, 11, 16, 18 and expression of p53 protein respectively in 44 specimens of LSCC. And 16 specimens of laryngeal polyp were selected as controls. RESULTS: 1. HPV genomes 16/18 were detected in 19 (43.2%) of 44 LSCCs and in 2 (12.5%) of 16 laryngeal polyps (P < 0.05). 2.25 (56.9%) of 44 specimens of LSCC were p53 protein positive whereas the laryngeal polyps were all p53 negative. 3. 12 (63.2%) of 19 HPV 16/18 DNA-positive specimens of LSCC showed p53 protein expression and 12 (48%) of 25 p53 protein positive specimens of LSCC showed HPV 16/18 infection. CONCLUSION: Expression of p53 protein and infection of HPV 16, 18 may play a role in carcinogenesis of LSCC, respectively or simultaneously.
After analyzing the time and frequency properties of ERP, a time-frequency filter based on multiresolution spline wavelet transform is proposed. This filter can effectively extracte the ERP from the eye-moving contaminated record.