Polymorphism of the tumor necrosis factor A gene in Melanesian and East-Asian populations.
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Alleles↗
Biomedical subjects
D Zhou
Publications and source records attributed to D Zhou.
Expression of genes implicated in multidrug resistance in acute lymphoblastic leukemia in India.
In order to investigate the phenomenon of multidrug resistance as a possible mechanism for poor response to treatment in patients with acute lymphoblastic leukemia (ALL) from India, a series of 32 cases of de novo untreated ALLs were analyzed by a cDNA-PCR approach to estimate the relative mRNA levels of the MDR-associated genes encoding MDR1, MRP, GSTpi, and GSTmu. The expression of beta2 microglobulin served as an internal standard. Quantifiable transcripts were observed in 20 patients for MRP, in 5 for MDR1, in 24 for GSTpi, and in 19 for GSTmu. The values ranged from undetectable to 132% of the control A549 cell line for MRP, undetectable to 49% of the HL60/DNR control cell line for MDR1, undetectable to 268% of A549 control cell line for GSTpi, and undetectable to 247% of A549 control cell line for GSTmu mRNA. Increased MRP levels were associated with increased GSTpi and GSTmu levels (p<0.01 for both), and increased levels of MDR1 were associated with increased GSTpi levels (p<0.05). The present observations showed no correlation between the MDR1 and MRP values with treatment outcome, in terms of either achieving a complete remission or predilection to early relapse. In view of some recent studies that envisage MRP as an energy-dependent pump involved in the efflux of GSH conjugates, the simultaneous up-regulation of transcription of all these genes might well be part of an integrated detoxification response that has been switched on after exposure to an environmental stress.
ATP-Binding Cassette Transporters↗
Transcriptional regulation of human transcription factor IIB in SMMC-7721 human hepatocellular carcinoma cells by all-trans-retinoic acid and phorbol 12-myristate 13-acetate.
The differential-display reverse transcription/polymerase chain reaction (DDRT-PCR) method was utilised to find genes differentially expressed at the messenger RNA level in SMMC-7721 human hepatocellular carcinoma cells treated and not treated with all-trans-retinoic acid, a differentiation inducer of the cell. Human transcription factor IIB (TFIIB) was discovered to be decreased on the 3rd day after the cells had been treated with retinoic acid and increased by phorbol 12-myristate 13-acetate, which stimulated the proliferation of human hepatocellular carcinoma cells. It was also found that the transcription of TFIIB in SMMC-7721 cell had no relationship to the cell cycle.
Antineoplastic Agents↗
A dose-response relationship between exposure to cockroach allergens and induction of sensitization in an experimental asthma in Hartley guinea pigs.
OBJECTIVE: An indoor allergen, cockroach allergen (CRa) has been partly implicated in the rising prevalence of inner-city asthma. This study investigates a dose-response relationship of exposure to CRa with the degree of sensitization and with airway inflammation through the use of our established guinea pig asthma model. METHODS: Four groups of Hartley guinea pigs were exposed to aerosolized saline (control) and three dose levels of CRa: low-dose, 0.5 mg (LD); medium-dose, 5 mg (MD); or high-dose, 25 mg (HD), nebulized twice a day, 5 days per week, for 4 weeks. The development of anaphylactic antibodies was measured by both allergy skin test and passive cutaneous anaphylaxis assay. Animals were challenged with CRa 5 days after the last sensitization, and specific airway resistance was measured continuously by a double-chamber plethysmograph while animals were in the conscious state. The inflammatory cells in bronchoalveolar lavage fluid (BALF) and the contractile responses of tracheal rings were analyzed in vitro at 24 hours after CRa challenge. RESULTS: The anaphylactic antibodies to CRa were detected in the CRa-sensitized animals by allergy skin test. Passive cutaneous anaphylaxis titers of IgG1a-like antibody were zero in control, 1:2 in LD, 1:40 in MD, and 1:160 in HD. Total leukocytes in BALF were increased by CRa challenge in all three CRa-sensitized groups compared with control (p < 0.0001). The tracheal rings from CRa-sensitized guinea pigs constricted upon addition of incremental doses of CRa challenge in vitro in a dose-responsive manner (p < 0.0001). The leukocytosis in BALF and the anaphylactic contractile responses of the tracheal rings in CRa-sensitized groups were correlated to the levels of CRa to which the groups had been exposed during sensitization (p < 0.001). CRa-provoked increase in SRaw was noted in all three groups of the CRa-sensitized guinea pigs compared with control (p < 0.01). Yet, among CRa-sensitized groups, a greater increase in specific airway resistance was noted in the LD group but not in the HD CRa group. CONCLUSIONS: The development of anaphylactic cockroach sensitivity in guinea pigs was dependent on the levels of CRa exposure during sensitization, and the CRa-sensitized animals showed antigen-specific airway inflammation along with airway smooth muscle contractions. However, the severity of bronchospasm in conscious animals was not in agreement with the degree of CRa sensitivity.
Allergens↗
Later orthodontic appliance reactivation stimulates immediate appearance of osteoclasts and linear tooth movement.
BACKGROUND: Delays in the appearance of osteoclasts at compression sites occur after orthodontic appliance reactivation, when this is done during both the period of osteoclast recruitment and the peak expansion in the osteoclast population. This experiment examines osteoclasts and tooth movement in alveolar bone after appliance reactivation coinciding with alveolar bone formation and the time when reactivation osteoclasts first appear (ie, 10 days after initial appliance activation). METHODS: Bilateral orthodontic appliances were activated to mesially tip maxillary molars with 40 cN in 144 rats. After 10 days, all rats were randomized into two groups of 72. Group I had appliances reactivated in precisely the same manner as the first activation. Group II had appliances sham-reactivated. Nine to 12 rats were then sacrificed at 1, 3, 5, 7, 10, and 14 days in both groups (eg, day 1 represents an interval of 11 days after the first appliance activation and 1 day after either sham or real reactivation). Orthodontic movement was measured cephalometrically; changes in osteoclasts and root resorption were assessed at both compression and tension sites histomorphometrically. RESULTS: Teeth in the reactivated group (Group I) displayed linear tooth movement (62.6 micrometers/day), and 0.9 mm tooth movement by day 10. Significant increases in osteoclast numbers, osteoclast surface percentage, and surface per individual osteoclast were evident in these animals by 1 day postreactivation (P <.01). Significant treatment-related increases in root resorption were not evident at compression sites at any time. CONCLUSIONS: These findings indicate that, after appliance reactivation during the time when reactivation osteoclasts appear, a second cohort of osteoclasts can be recruited immediately, along with immediate and substantial tooth movement and no greater risk of root resorption.
Alveolar Process↗
High prevalence of Helicobacter heilmannii infection in China.
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Adult↗
Developmental expression of spectrins in rat skeletal muscle.
Skeletal muscle contains spectrin (or spectrin I) and fodrin (or spectrin II), members of the spectrin supergene family. We used isoform-specific antibodies and cDNA probes to investigate the molecular forms, developmental expression, and subcellular localization of the spectrins in skeletal muscle of the rat. We report that beta-spectrin (betaI) replaces beta-fodrin (betaII) at the sarcolemma as skeletal muscle fibers develop. As a result, adult muscle fibers contain only alpha-fodrin (alphaII) and the muscle isoform of beta-spectrin (betaISigma2). By contrast, other types of cells present in skeletal muscle tissue, including blood vessels and nerves, contain only alpha- and beta-fodrin. During late embryogenesis and early postnatal development, skeletal muscle fibers contain a previously unknown form of spectrin complex, consisting of alpha-fodrin, beta-fodrin, and the muscle isoform of beta-spectrin. These complexes associate with the sarcolemma to form linear membrane skeletal structures that otherwise resemble the structures found in the adult. Our results suggest that the spectrin-based membrane skeleton of muscle fibers can exist in three distinct states during development.
Animals↗
Nonopsonic phagocytosis of group C Neisseria meningitidis by human neutrophils.
Although complement-mediated bactericidal activity in serum has long been known to be very important in host defense against Neisseria meningitidis, recent studies have shown that opsonic phagocytosis by neutrophils is also important. The purpose of this study was to determine if endemic group C N. meningitidis strains were susceptible to nonopsonic (complement- and antibody-independent) phagocytosis by human neutrophils, which is a well-described phenomenon for Neisseria gonorrhoeae. Gonococci that possess one or more of a group of heat-modifiable outer membrane proteins (called opacity-associated [Opa] proteins) are phagocytosed by neutrophils in the absence of serum. We found that four serogroup C meningococcal strains bearing the lacto-N-neotetraose (LNnT) structure on lipooligosaccharide (LOS) were phagocytosed by neutrophils in the absence of antibody and active complement. Confocal microscopy confirmed that the organisms were internalized by neutrophils. This susceptibility was not restricted to carrier isolates, since two of the strains were cultured from blood or cerebrospinal fluid. All four strains expressed Opa protein and had relatively less endogenous LOS and capsule sialylation compared to six strains that were resistant to this type of phagocytosis. Nonopsonic phagocytosis of two of the four strains was inhibited by exogenous sialylation of LOS LNnT and the binding of monoclonal antibody to LNnT. However, an isogenic mutant that lacked the LNnT structure was fully susceptible to nonopsonic phagocytosis. We conclude that group C meningococci can be phagocytosed by neutrophils in the absence of antibody and active complement possibly by two different mechanisms. Expression of Opa protein and downregulation of endogenous surface sialic acids analogous to what is seen for N. gonorrhoeae might be necessary for N. meningitidis as well.
Adult↗
In vitro and in vivo evaluation of insulin-producing beta TC6-F7 cells in microcapsules.
In the present study, the insulin secretory capacity of beta TC6-F7 cells in microcapsules was evaluated. The cell mass within capsules was found to expand in a three-dimensional fashion, in contrast to cells seeded on plates that grew as a monolayer. In in vitro studies, both free and encapsulated cells were found to secrete insulin in the absence of glucose, at 13.6 +/- 1.1 and 14.5 +/- 0.9 ng.10(6) cells-1.60 min-1, respectively, with the response rising to a maximum of 26.0 +/- 0.8 and 31 +/- 2.3 ng.10(6) cells-1.60 min-1 in the presence of 16.8 mM glucose. Encapsulated cells were able to produce Ca2+ responses in the presence of KCl (50 mM) and BAY K 8644 (100 microM). In in vivo studies, intraperitoneal transplantation of 3.0 x 10(6) microencapsulated cells into mice (n = 5) with streptozotocin-induced diabetes resulted in the restoration of normoglycemia up to 57 days. Insulin concentrations rose from 0.4 +/- 0.1 ng/ml before the graft administration to 2.2 +/- 0.8 ng/ml after the transplantation in the normoglycemic recipients. An oral glucose challenge in transplant recipients demonstrated a flat glucose response, suggesting extremely high glucose clearance rates. These data demonstrate the potential use of the immunoisolated beta-cell lines for the treatment of diabetes.
Animals↗
Contractile responses to allergen and cholinergic stimulation in bronchus and trachea of cockroach allergen-sensitized guinea pigs.
Airway hyperreactivity is a hallmark of asthma. Yet, the role of allergic sensitization in the hyperreactivity remains controversial. This study examined the effects of airborne cockroach allergen (CRa) sensitization on the contractility of bronchial (BSM) and tracheal (TSM) smooth muscle rings to cholinergic stimulations, and to specific antigen, in vitro. Guinea pigs were actively immunized with CRa, 5 mg (high dose, HD), 0.5 mg (low dose, LD), or saline aerosols (2x/day, 5 days/week, for 4 weeks) and challenged by CRa inhalation 5 days after last exposure. Twenty-four hours postchallenge, the contractions of the TSM and BSM to electrical field stimulation (EFS), acetylcholine (ACh), and to CRa were measured in vitro. In addition, the contraction to these stimuli were also examined in the passively sensitized TSM with the sera of CRa-immunized guinea pigs. The contractile responses of actively immunized and passively sensitized tissues to EFS and ACh were very similar to those of control tissues. CRa induced dose-dependent contractions in both actively immunized and passively sensitized, but not in control, tissues. The CRa-induced contraction was stronger in the HD group than in the LD group (p<0.0001). Leukotriene C4/D4 receptor antagonist LY-171883 inhibited the CRa-induced contraction by 86% in actively immunized TSM, and by 9% in the passively sensitized TSM. Pyrilamine inhibited the contraction by 57% in actively immunized TSM and 70% in passively sensitized TSM. The results indicate that CRa sensitization does not cause increased airway smooth muscle contractility to cholinergic stimulations, but induces antigen-specific contractions in vitro. Leukotrienes appear to play a significant role in the CRa-specific contractions, more in the actively immunized than those in the passively sensitized tissues, while histamine exerts a moderate effect on the CRa-induced contractions.
Acetophenones↗
Genetic engineering of glucose-stimulated insulin secretion in Chinese hamster ovary cells.
To engineer an a non-islet cell capable of glucose-stimulated insulin secretion, a chinese hamster ovary cell line (CHO) was transfected with a mammalian expression vector carrying the human insulin cDNA (pCB/hINS). More proinsulin than insulin was released daily by the stably transformed cell line (CHO-INS). Examination of acid-ethanol extracts confirmed that both insulin and proinsulin were stored. Immunohistochemical analysis of the cells also showed that (pro)insulin was stored. Unlike beta cells, CHO-INS cells did not secrete insulin in response to glucose. To investigate this lack of effect, we examined whether transfection of GLUT2 cDNA, which is ordinarily not expressed in CHO-INS cells, would confer glucose-stimulated insulin secretion. Consequently, we have demonstrated that glucose regulated insulin release occurs in the CHO-INS-GLUT2 cell line and that glucose potentiates the insulin secretory response to non-glucose secretagogues.
Animals↗
Clinical studies on diffuse axonal injury in patients with severe closed head injury.
OBJECTIVE: To discuss the clinical criteria for diagnosing diffuse axonal injury (DAI). METHODS: Clinical and computed tomographic features of 117 patients with severe closed head injury were analyzed. The authors preliminarily put forward CT diagnostic criteria of DAI, that is, 1) single or multiple small intraparenchymal hemorrhages in the cerebral hemispheres (< 2 cm in diameter); 2) intraventricular hemorrhage; 3) hemorrhage in the corpus callosum; 4) small focal areas of hemorrhage adjacent to the third ventricle (< 2 cm in diameter); and 5) brain stem hemorrhage. All patients were divided into two groups, DAI and non-DAI group, according to the criteria. There were 42 patients in the DAI group and 75 patients in the non-DAI group. The injury causes, Glasgow coma scale (GCS) scores on admission, coexisting injuries and outcomes were compared between the two groups. The relationship between DAI and the outcomes in the patients with severe head injury was analyzed. RESULTS: Traffic accident was the main injury cause in the cases of DAI. GCS scores on admission in patients with DAI were significantly lower than those in patients without DAI. The incidence of diffuse brain swelling (DBS) in the DAI group was significantly higher than that in the non-DAI group, whereas the incidences of both skull fracture and epidural hematoma (EDH) in the DAI group were significantly lower than those in non-DAI group. There was no significant difference between the incidence of subarachnoid hemorrhage (SAH) and subdural hematoma (SDH) in the two groups. The incidence of poor outcome in the DAI group was significantly higher than that in the non-DAI group, although there was no significant difference between the mortalities in the two groups. CONCLUSIONS: Because DAI is a very important factor worsening the outcome of patients with head injury, it is essential to make a diagnosis as soon as possible. The clinical manifestations of DAI, however, are not specific and DAI does not show directly on CT scans, so it is difficult to make a definite diagnosis. The CT diagnostic criteria of DAI put forward in this article are practicable, though they are by no means perfect.
Adolescent↗
Fast assay and mini-purification of protein by high performance membrane affinity chromatography.
Several affinity ligands of protein A, human immunoglobulin G, iminodiacetate (IDA)-Cu2+, and cibacron blue F3GA were coupled to GMA-modified cellulose membrane matrices. We prepared the columns based on the membrane supports in high performance membrane affinity chromatography (HPMAC). Next we evaluated nonspecific adsorption of proteins on the membrane media. The rapid assay of proteins on the affinity columns based on membrane supports was achieved. It was observed that the affinity columns based on membrane supports provided good reproducibility, high separation efficiency, and low pressure drop of the column. The columns with the membrane media could also be used for purification of proteins.
Adsorption↗
[The expression of CD11a and CD11b on leucocytes in cerebral thrombosis].
This study sought to understand the mechanism for the increased adhesion of leucocytes and endothelial cells in ischemic stroke. 20 patients with acute cerebral thrombosis and 20 healthy subjects as controls for expression of CD11a and CD11b (adhesion molecules on surface of leucocytes) were tested in vitro by flow cytometry (FCM) method. The results showed that compared with the control group, the patient group had significantly higher rates for expression of CD11a on monocytes, granulocytes and lymphocytes (P < 0.05). The CD11b expression in the patient group was positively elevated on monocytes and granulocytes (P < 0.05), but it was of lower positive rate on lymphocytes and no statistical difference was noted between the patient and control groups. These indicate that the expression of CD11a and CD11b on leucocytes increases in cerebral ischemic damage; thus adhesion of leucocytes and endothelial cells obviously increases. This change may aggravate post-ischemic delayed neuronal death.
Adult↗
[Biological diagnostic and therapeutic study on the infection of Helicobacter heilmannii].
OBJECTIVE: To study the epidemiology, microbiology, pathogenicity, diagnosis and therapy of Helicobacter heilmannii (Hh) infection. METHODS: Morphological methods, such as Gram staining of gastroscopic biopsy smears, Giemsa staining of histological slides and scanning electromicroscopy(SEM), and biochemistry techniques such as urease test(CLO), 14C urea breath test(UBT) were used to identify Hh infection in natural populations. The 16S rRNA gene of 4 strains of Hh were amplified, sequenced and analysed, using bacterial universal and Helicobacter genus-specific primers. RESULTS: Twenty cases of Hh infection were found in 992 peoples with the positive rate of 2.0%. There existed the phenomena of intrafamily cluster of Hh infection. 14 case of the gastic tissues were CLO positive and 3 cases of these patients were UBT positive, the bacterium cannot be isolated in vitro. Sporadic invasion of lymphocyte/plasmic cell were found in gastric mucosa with Hh infection. Formation of lymph follicles and invasion of neutrophlic cell could be found too. The "old triple therapy" regimen could eradicate Hh easily. The homology of 16S rRNA gene among 4 strains was between 98.7%-99.7%, and can not be devided into two subtypes. The homology between Hh and H. felis or Hp were 95.6%-96.5% and 96.4%-97.1%, respectively. CONCLUSION: The prevalence of Hh in southern China is higher than that reported abroad. There may exist animal to person and person to person transmission mechanisms. Hh should be a new Helicobacter with lower activity of urease and weaker pathogenicity when compared with H. pylori. The infection of Hh is easy to eradicate through drug therapy.
Adolescent↗
[Determination of HIgG in Human plasma by high performance membrane affinity chromatography(HPMAC)].
An assay technique for determination of Human IgG in human plasma has been developed by utilizing Protein A bound to the modified cellulose matrices based on the strong affinity between protein A and Fc region of IgG. The pH values of loading buffer and elution buffer were 7.0 and 2.3 respectively. The cartridge used was 20 mm x 4 mm i.d. and detection was carried out with a UV monitor at 280 nm. The non-specific adsorption of two kinds of media has been studied. The media without hexyldiamine arm gives very low non-specific adsorption BSA. The calibration curve showed a good linearity (correlation coefficient > 0.9992) in the injected amount range of 9-70 micrograms for HIgG. The total time for separation and determination was within 5 min and the total time of rapid assay was within 30 s. Relative standard deviations of peak areas were 1.5% (n = 5) and 3.6% (n = 3) for HIgG in standard solution and human plasma respectively.
Chromatography, Affinity↗
[Corneal topography analysis after excimer laser photorefractive keratectomy].
OBJECTIVE: To study the pattern of ablation, evaluate centration and stability following excimer laser photorefractive keratectomy (PRK) for myopia. METHOD: Corneal topography of 312 patients (366 eyes) with a month, 3 months and 6 months of follow-up after PRK was examined. RESULTS: The mean decentration from the pupillary center to ablating center was 0.266 mm. In both eyes, the mean decentration was located supernasally. At one month postoperative examination, uniform ablation was 49.5%, semicircular, keyhole, kidney and dumbbell shaped ablations were 42.9% and central island one was 6.0%. Central island pattern affected the best corrected visual acuity greatly. High myopia began regression at 1-3 months after PRK. CONCLUSION: Corneal topography is essential for evaluating surface changes after PRK. Long-time stability issues are answered with continued topographic follow-up.
Corneal Topography↗
[Excimer laser in situ keratomileusis for treatment of myopia].
OBJECTIVE: To evaluate the effectiveness of excimer laser in situ keratomileusis (LASIK) for treatment of myopia. METHODS: 928 eyes of 678 myopic patients who received LASIK were studied. The patients were divided into 3 groups according to preoperative diopters (-2.00 - -6.00D, -6.10 - -10.00D & -10.10 - -20.00D). The mean follow-up was 12 months (6 - 18 months) and the results were statistically analyzed. RESULTS: 12 months after surgery, in the first group the mean residual refraction was -0.24 +/- 0.50D in 86% and 92% of eyes were in the ranges of refraction +/- 0.50D and +/- 1.00D, the uncorrected visual acuities of 0.5 and 1.0 were in 99% and 86% of the eyes respectively. In the second group, the mean residual refraction was -0.47 +/- 0.64D, the refraction of 83% and 90% of eyes was in the ranges of +/- 0.50D and +/- 1.00D, and the uncorrected visual acuities in 95% and 79% of eyes were 0.5 and 1.0 respectively. In the third group, the mean residual refraction was -0.89 +/- 1.02D, the refraction of 36% and 62% of the eyes were in the ranges of +/- 0.50D and +/- 1.00D, and the uncorrected visual acuities in 68% and 45% of the eyes were 0.5 and 1.0 respectively. 47 eyes had been retreated with LASIK. 5 eyes lost two or more lines of the best corrected visual acuity due to irregular astigmatism, decentration and progressive myopic maculopathy. CONCLUSION: The results indicate that LASIK can treat myopia in the range of -2.00 - -20.00 D effectively without vision threatening complications. Some modification of the surgical techniques and laser nomogram will help to improve predictability and stability of outcome.
Adolescent↗