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Biomedical subjects

C Ding

Publications and source records attributed to C Ding.

At least 37 records · Page 2Linked to original sources
PubMed2000

In vivo indomethacin treatment causes microglial activation in adult mice.

The current study was undertaken to study the role of prostaglandins in regulating microglial activation. Mice were treated with indomethacin (2 microg/ml) in their drinking water to selectively inhibit cyclooxygenase activity. After 4-8 days, the effect of inhibiting prostaglandin synthesis on microglial activity was evaluated. This was accomplished by analyzing microglial expression of Mac-1 (C3 complement receptor) as an indicator of activation. Mac-1 expression was assessed by immunohistochemistry of fixed brain cryosections, and by flow cytometric analysis of immunostained single cell suspensions. Both methods demonstrated that compared to age-matched, untreated controls, brains of indomethacin-treated mice had increased levels of Mac-1 expression, suggesting an increase in the state of microglial activation. These results demonstrate the importance of prostaglandins in down regulating microglial activity, and that inhibition of prostaglandin synthesis with indomethacin may act to increase the reactivity of the brain's immune system.

Animals↗
PubMed2000

Salivary glands as a model for craniofacial applications of gene transfer.

The potential applications of gene transfer technology to all branches of medicine are increasing. It is quite likely that within the next 10-20 years surgical practice routinely will utilize gene transfer, at least adjunctively. The purpose of this review is to familiarize the oral and maxillofacial surgeon with this technology. Studies performed with salivary glands in animal models are presented as examples of proof of concept.

Animals↗
PubMed2000

[Studies on schedules for human rabies immunization].

OBJECTIVES: To study the feasibility of interferon (INF) plus an immunization schedule of two dose-two dose-one dose (2 - 2 - 1) of rabies vaccine and a simple 2 - 2 - 1 schedule, and to explore immune regulation mechanism of INF. METHODS: For an IFN plus 2 - 2 - 1 schedule, 5.0, 5.0 and 2.5 I.U. of primary hamster kidney cell rabies vaccine (PHKCV) were injected on the 1st, 7th and 14th day, respectively, and 0.2 million I.U. of IFN-alpha on the 1st day simultaneously. For a simple 2 - 2 - 1 schedule, only 5.0, 5.0 and 2.5 I.U. PHKCV were injected on the 1st, 7th and 14th day, respectively. And, for controls, a routine schedule recommended by WHO was used. RESULTS: On the 7th day after immunization, their geometric mean titer (GMT) of antibody was 1.71, 1.57 and 1.21 for the above three schedule groups, respectively; on the 14th day, 62.77, 58.79 and 28.96; on the 45th day, 76.64, 72.90 and 62.22. Conversion rate of antibody was 85.00%, 61.11% and 65.00%, respectively on the 7th day, and was 100.00% for all on the 14th day. Proportion of those with protective antibody level was 10.00%, 0.00% and 0.00%, respectively for the three schedule groups, on the 7th day; 100.00%, 100.00% and 95.00%, on the 14th day; and was 100.00% for all on the 45th day. Proportion of those with antibody titer more than 1:1 was 55.00%, 33.33% and 20.00%, respectively, on the 7th day. Adverse reaction rate was 0.00% - 55.00%, without significant difference between three schedule groups. CONCLUSIONS: Lower dose of IFN could enhance the effect of immune response to rabies vaccine. IFN plus 2 - 2 - 1 rabies vaccine schedule was better than that of simple 2 - 2 - 1 schedule, while the later was better than the routine schedule.

Adolescent↗
PubMed1999

Long-term correction of phagocyte NADPH oxidase activity by retroviral-mediated gene transfer in murine X-linked chronic granulomatous disease.

Chronic granulomatous disease (CGD) is an inherited deficiency of the superoxide-generating phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, resulting in recurrent, severe bacterial and fungal infections. The X-linked form of this disorder (X-CGD) results from mutations in the X-linked gene for gp91(phox), the larger subunit of the oxidase flavocytochrome b(558). In this study, we used a murine model of X-CGD to examine the long-term function of retroviral vectors for expression of gp91(phox) based on the murine stem cell virus (MSCV) backbone. NADPH oxidase activity was reconstituted in neutrophils and macrophages for up to 18 to 24 months posttransplantation of transduced X-CGD bone marrow into lethally irradiated syngeneic X-CGD mice. Southern blot analysis and secondary transplant data showed proviral integration in multilineage repopulating cells. Although relatively small amounts of recombinant gp91(phox) (approximately 5% to 10% of wild-type levels) were detected in neutrophils after retroviral-mediated gene transfer, superoxide-generating activity was approximately 20% to 25% of wild-type mouse neutrophils. Expression of gp91(phox) is normally restricted to mature phagocytes. No obvious toxicity was observed in other hematopoietic lineages in transplant recipients, and provirus-marked cells were capable of reconstituting secondary transplant recipients, who also exhibited NADPH oxidase-positive neutrophils. MSCV-based vectors for long-term expression of gp91(phox) may be useful for gene therapy of human CGD targeted at hematopoietic stem cells.

Animals↗
PubMed1999

Post-therapy serum prostate-specific antigen level and survival in patients with androgen-independent prostate cancer.

BACKGROUND: With an hypothesis that post-chemotherapy changes in serum prostate-specific antigen (PSA) levels might serve as a surrogate marker for assessing prostate cancer outcome (i.e., survival), we studied the relationship between pretherapy and post-therapy prognostic factors and survival in patients with androgen-independent prostate cancer. METHODS: A prognostic model for survival based on pretherapy and post-therapy parameters was developed from the clinical data on 254 patients with androgen-independent prostate cancer treated with 11 different protocol therapies at Memorial Sloan-Kettering Cancer Center. The model was validated by use of an independent dataset of 541 patients enrolled in two randomized phase III trials. RESULTS: In multivariate analysis, a post-therapy decline in PSA levels of 50% achieved in 12 weeks was a statistically significant factor associated with survival (two-sided P = .0012). A similar outcome was obtained with the use of an 8-week time frame. Elevated pretherapy level of serum lactate dehydrogenase (two-sided P = .0001), lower pretherapy level of hemoglobin (P = .0001), and younger age (two-sided P = .0430) had a statistically significant negative impact on outcome. Median survival times were 23, 17, and 9 months for low-, intermediate-, and high-risk groups of patients defined by the prognostic model, respectively. CONCLUSION: This study confirms the prognostic value of a post-therapy decline in PSA of 50% or greater from baseline in relation to survival in patients with androgen-independent prostate cancer treated with a variety of therapies. Two consecutive determinations at 4-week intervals can be used as an end point for efficacy in phase II trials of therapies in this disease.

Aged↗
PubMed1999

Prognostic significance of extent of disease in bone in patients with androgen-independent prostate cancer.

PURPOSE: To evaluate the prognostic significance of a bone scan index (BSI) based on the weighted proportion of tumor involvement in individual bones, in relation to other factors and to survival in patients with androgen-independent prostate cancer. PATIENTS AND METHODS: Baseline radionuclide bone scans were reviewed in 191 assessable patients with androgen-independent disease who were enrolled onto an open, randomized trial of liarozole versus prednisone. The extent of skeletal involvement was assessed by scoring each scan using the BSI and independently according to the number of metastatic lesions. The relationship of the scored bone involvement to other known prognostic factors was explored in single- and multiple-variable analyses. RESULTS: In single-variable analyses, the pretreatment factors found to be associated with survival were age (P = .0446), performance status (P = .0005), baseline prostate-specific antigen (P = .0001), hemoglobin (P = .0001), alkaline phosphatase (P = .0002), AST (P = .0021), lactate dehydrogenase (P = .0001), and treatment (P = .0098). The extent of osseous disease was significant using both the BSI (P = .0001) and the number of lesions present (P = .0001). In multiple-variable proportional hazards analyses, only BSI, age, hemoglobin, lactate dehydrogenase, and treatment arm were associated with survival. When the patient population was divided into three equal groups, with BSI values of < 1.4%, 1.4% to 5.1%, and > 5.1%, median survivals of 18.3, 15.5, and 8.1 months, respectively, were observed (P = .0079). CONCLUSION: The BSI quantifies the extent of skeletal involvement by tumor. It allows the identification of patients with distinct prognoses for stratification in clinical trials. Further study is needed to assess the utility of serial BSI determinations in monitoring treatment effects. The BSI may be particularly useful in the evaluation of agents for which prostate-specific antigen changes do not reflect clinical outcomes accurately.

Aged↗
PubMed1999

[A clinico-pathological and immunohistochemical study on anaplastic large cell lymphoma].

OBJECTIVE: To study the clinicopathological characteristics, immunophenotype and biologic behavior of anaplastic large cell lymphoma (ALCL). METHODS: Clinicopathological and immunohistochemical methods (ABC method) were used to analyse 8 cases of ALCL and followed for 6 to 25 months. RESULTS: Eight ALCL patients (4 male and 4 female) accounted for 4.1% of the 195 lymphomas seen from 1994 to 1997. Average age was 40 years. Two tumors were located in the skin, the remainder were systemic. Clinical stage: stage I, 2 cases; stage II, 1 case; stage III, 5 cases. Histopathology: Tumor cells exhibited high pleomorphism and a large amount of mitotic figures. Reactive components (cells) often observed in the background. Immunohistochemical studies found that all tumors reacted positively with CD30 and negatively with CD15. Five cases expressed T-cell's markers (CD3, UCHL-1, CD43) and three expressed B-cell markers (CD79a, L26). After chemotherapy, two patients with cutaneous type ALCL had complete remission and survived 14 and 25 months respectively. Of the six systemic cases, three survived for 6-8 months, the remaining three died at 2 days, 20 days and 18 months after diagnosis. CONCLUSIONS: This study found that ALCL was a group of lymphomas showing similarity in morphology but diversity in clinical presentation and immunophenotype. Even if the tumor is very responsive to chemotherapy, ALCL remains a high grade malignant lymphoma.

Adolescent↗
PubMed1998

The utility of Hayashi's quantification theory type 2 for the rapid assessment of the epidemiological survey in the developing countries--in a case of the vaccine coverage survey in Yunnan Province, China.

It is difficult to conduct the epidemiological survey with accurate statistical theory in the developing countries due to the problems especially emerged in the developing countries such as no availability of the accurate population data, limitation of the time for survey, geographical obstacle and financial problems. In the consideration of the health needs in those countries, results of the epidemiological survey should be reflected in the present health projects as rapidly as possible. The authors conducted the survey for the immunization coverage of oral poliomyelitis vaccine(OPV) in China by the questionnaire and interview. The data was analyzed by using the Hayashi's quantification theory type 2 and made clear about the relationship between the health behaviors for immunization among residents and several factors. It is considered that this theorem can provide the obvious numeral materials about multi-factorial cause effect relationship for the decision making and is useful for the rapid assessment or initial survey in the developing countries.

Chi-Square Distribution↗
PubMed1998

[Effect of fighter cockpit noise on pilot hearing].

In order to describe quantitatively the pilots' hearing injury by noise in fighter cockpit, the noise level was measured in the cockpit. The temporary threshold shift (TTS) was studied in 20 healthy young man and permanent threshold shift was examined in 166 fighter pilots. The results showed that noise level in cockpit was 110 dBA and TTS after 2 min noise exposure decreased significantly and reached 13 dB at a certain frequency. Its recovery course is faster in low frequency part and language frequency part than that in high frequency part. It was also found that 56% of the 166 pilots suffered from high frequency hearing loss and the percentage increased with flight time. The feature of hearing loss is that it occurs in high frequency at first, then in language frequency, forming a "V" shaped depression at 6 000 Hz. It indicates that cockpit noise may cause permanent threshold shift of hearing.

Adolescent↗
PubMed1998

[Determination of Cd, Cu, Pb, Hg by reversed-phase high performance liquid chromatography].

The chromatographic behaviors of Me(n+)-Dz (dithizone) have been studied with RP-HPLC. A method for the determination of Cd, Cu, Pb and Hg has been established. The chromatographic conditions were: column: Shim-pack CLC-ODS, 150 mm x 6.0 mm i.d.; mobile phase: V(methanol): V(water): V (chloroform) (containing volume fraction 1% triethylamine) = 80:12:8; flow rate: 1 mL/min; column temperature: 35 degrees C; detection wavelength: 254 nm. The linear ranges were from 0.01 mg/mL to 2.0 mg/mL with correlation coefficients of 0.9993-0.9998. The detection limits of Cd, Cu, Pb, Hg were from 2.4 micrograms/L to 5.0 micrograms/L. The RSDs were in the range from 1.8% to 9.7%, and the recoveries ranged from 94% to 103% (except Hg). The method has been applied to the analysis of hair.

Cadmium↗
PubMed1997

Retroviral-mediated gene transfer of gp91phox into bone marrow cells rescues defect in host defense against Aspergillus fumigatus in murine X-linked chronic granulomatous disease.

The X-linked form of chronic granulomatous disease (X-CGD), an inherited deficiency of the respiratory burst oxidase, results from mutations in the X-linked gene for gp91phox, the larger subunit of the oxidase cytochrome b. The goal of this study was to evaluate the impact of retroviral-mediated gene transfer of gp91phox on host defense against Aspergillus fumigatus in a murine model of X-CGD. Retrovirus vectors constructed using the murine stem cell virus (MSCV) backbone were used for gene transfer of the gp91phox cDNA into murine X-CGD bone marrow cells. Transduced cells were transplanted into lethally irradiated syngeneic X-CGD mice. After hematologic recovery, superoxide production, as monitored by the nitroblue tetrazolium (NBT) test, was detected in up to approximately 80% of peripheral blood neutrophils for at least 28 to 35 weeks after transplantation. Neutrophil expression of recombinant gp91phox and superoxide production were significantly less than wild-type neutrophils. However, 9 of 9 mice with approximately 50% to 80% NBT+ neutrophils after gene transfer did not develop lung disease after respiratory challenge with 150 to 500 A fumigatus spores, doses that produced disease in 16 of 16 control X-CGD mice. In X-CGD mice transplanted with mixtures of wild-type and X-CGD bone marrow, > or = 5% wild-type neutrophils were required for protection against A fumigatus challenge. These data suggest that expression of even low levels of recombinant gp91phox can substantially improve phagocyte function in X-CGD, although correction of very small percentage of phagocytes may not be sufficient for protection against A fumigatus.

Animals↗
PubMed1997

First trial of home ECG and blood pressure telemonitoring system in Macau.

OBJECTIVE: To determine the feasibility of home monitoring of patients with cardiac disease or hypertension. METHODS: An improved home electrocardiographic and blood pressure telemonitoring system linked to a central workstation was tested in 10 patients in Macau for 3 months. RESULTS: The total number of connections was 1377. Of the automatic alarm connections, 32.5% were false positive, with the percentage of false positives ranging from 7.6 to 54.6 for different patients. Both patients and physicians found the system easy to use. CONCLUSIONS: Further investigation is required to match the number of patients with the system capacity. A more robust dysrhythmia detection algorithm is needed to reduce the number of false alarms. Nevertheless, the results were sufficiently good that the trial is being expanded.

Blood Pressure Determination↗
PubMed1997

cGMP stimulates sodium and chloride currents in rat tracheal airway epithelia.

To test the hypothesis that guanosine 3',5'-cyclic monophosphate (cGMP) regulates ion transport in airway epithelial cells, we measured short-circuit current (I(sc)) and (22)Na+ fluxes in primary cultured rat tracheal epithelial cells. In Cl- -containing Ringer solution, I(sc) was increased by approximately 17 microA/cm2 after application of 1 mM 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP), whereas, in Cl- -free solutions, the Na+ -mediated component was approximately 5 microA/cm2, suggesting a cGMP stimulation of Cl-secretory current and a smaller Na+ absorptive current. Inward and net mucosal-to-serosal (22)Na+ flux was doubled in the presence of 2 mM 8-BrcGMP. To determine whether nucleotide-gated channels play a role in this transepithelial Na+ absorption, blockers of nucleotide-gated cation channels were used to inhibit I(sc). The cGMP-stimulated Na+-mediated I(sc) was blocked by as little as 500 nM dichlorobenzamil or 50 microM L-cis-diltiazem, which are known blockers for cyclic nucleotide-gated cation channels. These agents also blocked the basal (non-cGMP-stimulated) current when measured in the presence of 10 microM amiloride, which blocks current through 5-pS amiloride-sensitive Na+ channels. To document whether the distribution of nucleotide-gated nonselective cation channels was consistent with a role in airway epithelial transport, in situ hybridization was performed. In situ hybridization of mRNA encoding for nucleotide-gated cation channels was found in epithelial cell layers of rat trachea, bronchi, bronchioles, and alveolar cells but not in smooth muscle layers or tracheal cartilage. Reverse transcriptase-polymerase chain reaction, restriction enzyme analysis, and sequencing of the cDNA transcribed from mRNA of whole lung and tracheal epithelial cells indicate that a channel highly homologous to the retinal nucleotide-gated nonselective cation channel (CNG1) is present. Thus these data, along with evidence supporting the existence of signal transduction pathways elevating intracellular levels of cGMP, indicate that cGMP regulates transepithelial ion transport in lung epithelial tissues.

Amiloride↗
PubMed1997

Cloning and widespread distribution of the rat rod-type cyclic nucleotide-gated cation channel.

We used Northern blot analysis, ribonuclease protection assay (RPA), reverse transcriptase-polymerase chain reaction, and in situ hybridization to investigate the hypothesis that the CNG1 isoform of the cyclic nucleotide-gated nonselective cation channel may be widely distributed in tissues of the rat. A cDNA encoding the CNG1 isoform was isolated from rat eye and human retina, and partial sequences were isolated from rat pineal gland and human kidney. Northern blot analysis revealed a 3.1-kilobase (kb) CNG1 transcript in rat eye, pineal gland, pituitary, adrenal gland, and spleen, and a larger transcript of 3.5 kb was found in testis. RPA confirmed the identity of CNG1 mRNA in rat eye, lung, spleen, and brain. Polymerase chain reaction-based detection of the mRNA for CNG1 indicates that the channel is expressed in lower abundance in many other tissues, including thymus, skeletal muscle, heart, and parathyroid gland. The cellular distribution of CNG1 was further studied by in situ hybridization, which demonstrated expression of mRNA in lung, thymus, pineal gland, hippocampus, cerebellum, and cerebral cortex but not in heart or kidney.

Amino Acid Sequence↗
PubMed1997

A home electrocardiography and blood pressure telemonitoring system.

A home electrocardiography (ECG) and blood pressure telemonitoring system for cardiac patients was installed in the Macau region. The monitoring centre was established in the emergency unit at the Government Hospital of Macau. The first users were 10 cardiovascular patients selected by a physician. The average age of these users was 61 years (range 30-78). The results of a three-month trial showed that the system was easy to operate and technically reliable. It was found to be helpful for cardiac patients. The most significant problem during the trial was electrical noise from the ECG electrodes.

Adult↗
PubMed1997

[Contrast sensitivity of several blindness-inducing eye diseases and the influence of tinted filter lens].

OBJECTIVES: To evaluate the effects of tinted filter lens on the visual rehabilitation of blind and low vision patients induced by optic nerve atrophy, glaucoma and retinitis pigmentosa. METHODS: The contrast sensitivity of 22 cases with optic nerve atrophy (34 eyes), 17 glaucoma (30 eyes), 18 retinitis pigmentosa (30 eyes) and 30 normal people (60 eyes) with and without yellow and red filter lens was tested. RESULTS: The results demonstrated that a yellow filter lens could improve the optic nerve atrophy patient's contrast sensitivity at 1.5, 3, 6 and 12 c/deg, while a red filter lens could increase the contrast sensitivity at limited spatial frequencies, but it could also decrease the contrast sensitivity at some other spatial frequencies. CONCLUSION: Yellow filter lens could be applied as a non-optical visual aid in the visual rehabilitation of the blind and low vision patients induced by these three diseases, as the above results show contrast sensitivity improvement in the low spatial frequency and the peak of the contrast sensitivity curves.

Adolescent↗
PubMed1997

[cDNA cloning, sequencing and expression of recombinant human prorelaxin].

In order to accelerate the development of biological recombinant human prorelaxin in our country, direct cloning of human prorelaxin gene from freshly prepared corpus luteum of Chinese woman by RT-PCR method was conducted. Isolated prorelaxin gene contains B, A chains and connective peptide. The amplified products were cloned and confirmed by DNA sequencing using Sanger Dideoxy method. It was subcloned into LKB2, a prokaryotic expression vector offering promoter LacI control, and highly expressed in E. coli. The results suggest that the PCR amplified DNA fragment shared identical sequence with known prorelaxin gene reported abroad. The SDS-PAGE analysis revealed that the expressed protein accounted for about 30% of the total cell protein, its MW was approximately 20 kD and conformed soluble protein.

Cloning, Molecular↗