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Biomedical subjects

L Ding

Publications and source records attributed to L Ding.

At least 55 records · Page 3Linked to original sources
PubMed2000

Novel fluorescent protein from Discosoma coral and its mutants possesses a unique far-red fluorescence.

A novel gene for advanced red-shifted protein with an emission maximum at 593 nm was cloned from Discosoma coral. The protein, named dsFP593, is highly homologous to the recently described GFP-like protein drFP583 with an emission maximum at 583 nm. Using the remarkable similarity of the drFP583 and dsFP593 genes, we performed a 'shuffling' procedure to generate a pool of mutants consisting of various combinations of parts of both genes. One 'hybrid gene' was chosen for subsequent random mutagenesis, which resulted in a mutant variant with a uniquely red-shifted emission maximum at 616 nm.

Amino Acid Sequence↗
PubMed2000

HSP43, a small heat-shock protein localized to specific cells of the vulva and spermatheca in the nematode Caenorhabditis elegans.

Heat-shock protein 43 (HSP43) of Caenorhabditis elegans is prominently expressed in the utse cell, which attaches the uterus to the hypodermis, the uv1 cells joining the vulva and the uterus, the spermathecal valve and junctions between cells of the spermathecal cage. In body-wall muscle, HSP43 forms a punctate pattern of circumferential lines, probably corresponding to regions where the hypodermis contacts the muscle cells.

Animals↗
PubMed2000

A comparison of three tests to detect general clustering of a rare disease in Santa Clara County, California.

Statistical tests to detect clustering of a rare disease investigate whether an observed spatial pattern of cases appears to be due to chance alone. Heterogeneous population density and the geographic structure of the data under consideration complicate the ability to make comparisons of different tests. Further, interpretation of test results depends on the nature of the test used and what feature of the data it is designed to detect. With these issues in mind, we compare three recent tests for assessing general clustering among cases where the population is distributed heterogeneously across the study area, namely those of Besag and Newell, Turnbull et al. and Tango. We compare these methods using 1981 incidence data for severe cardiac birth defects from Santa Clara County, California.

California↗
PubMed2000

HSP25, a small heat shock protein associated with dense bodies and M-lines of body wall muscle in Caenorhabditis elegans.

HSP25, a previously uncharacterized member of the alpha-crystallin family of small heat shock proteins in Caenorhabditis elegans, has been examined using biochemical and immunological techniques. HSP25 is the second largest of 16 identifiable small heat shock proteins in the nematode and is expressed at all developmental stages under normal growth conditions. Recombinant HSP25 produced in Escherichia coli exists predominantly as small oligomers (dimers to tetramers) and possesses chaperone activity against citrate synthase in vitro. In C. elegans, HSP25 is localized to dense bodies and M-lines in body wall muscle, to the lining of the pharynx, and to the junctions between cells of the spermathecal wall. Affinity chromatography of nematode extracts on a column of immobilized HSP25 resulted in specific binding of vinculin and alpha-actinin but not actin, as revealed by Western blotting. These results suggest a role for HSP25 in the organization or maintenance of the myofilament lattice and adherens junctions in C. elegans.

Amino Acid Sequence↗
PubMed2000

Evaluation of human diacylglycerol kinase(iota), DGKI, a homolog of Drosophila rdgA, in inherited retinopathy mapping to 7q.

PURPOSE: To determine the genomic organization of diacylglycerol kinase(iota) and to test whether defects in this gene are present in individuals affected with autosomal dominant retinitis pigmentosa (adRP). Diacylglycerol kinase(iota) has been mapped to the RP10 locus on 7q and shows 49% sequence similarity to the Drosophila DGK2 rdgA gene. Since mutations in the DGK2 rdgA gene cause photoreceptor degeneration in Drosophila, it is possible that mutations in diacylglycerol kinase(iota) could be responsible for human retinal degeneration. METHODS: DNA sequence from genomic clones containing diacylglycerol kinase(iota) was compared with the cDNA sequence to identify intron/exon boundaries. Single-strand conformational analysis and PCR product sequencing were used to screen members of one family previously mapped to the RP10 locus and 47 small unmapped families with autosomal dominant retinitis pigmentosa. RESULTS: Diacylglycerol kinase(iota) is divided into 35 exons with the initiation codon being present in exon 2. Mutational analysis found a missense change (Lys153Phe) in three adRP families; however, it did not segregate with disease in one of the families. Silent substitutions were seen in codons 865 and 875. Intronic variation was detected in the amplifications of exons 3,5,18, 28, and 32; these do not affect splice site consensus sequences. Typing of a polymorphic variant detected in intron 31 in members of the RP10 family gave a LOD score of -4.2 at 0% recombination. CONCLUSIONS: No evidence of disease-associated mutations was found in any of the samples tested. Based on the linkage data and mutation screening, diacylglycerol kinase(iota) is excluded as a candidate for the RP10 form of adRP and cannot be a frequent cause of other forms of adRP. Mutations in diacylglycerol kinase(iota) may yet be the cause of recessive forms of retinal degeneration in humans, either in homozygous or compound heterozygous forms. The data provided here will permit testing of this hypothesis.

Adult↗
PubMed2000

Effective gene therapy for pancreatic cancer by cytokines mediated by restricted replication-competent adenovirus.

Pancreatic cancer has a poor prognosis even when surgical treatment can be accomplished. Studies have demonstrated that pancreatic cancer is associated with various genetic abnormalities in oncogenes and tumor suppressor genes including p53. New therapeutic approaches for pancreatic cancer can be developed by targeting these genetic alterations. Adenovirus (Adv) lacking the 55-kDa E1B protein (E1B55K) replicates preferentially in p53-deficient cancer cells. We constructed E1B55K-deleted Adv (AxE1AdB), and studied its replication and cytopathic effect on pancreatic cancer cells. AxE1AdB replicated in and caused cell death of the p53-deficient pancreatic cancer cell lines tested (e.g., PANC-1, MIAPaCa-2, SU.86.86, BxPC-3, and PK-1). To enhance its therapeutic effect, we examined the combination of coinfecting this restricted replication-competent adenovirus (RRCA) with other Adv. Coinfection of E1-deficient Adv expressing the reporter lacZ gene (AxCAlacZ) together with AxE1AdB resulted in the replication of both viruses and a marked increase in reporter gene expression. PANC-1 cells coinfected with AxE1AdB and the Adv for human IL-2 (AxCAhIL2), produced 110 times more IL-2 than those infected with AxCAhIL2 alone. Similarly, coinfection of AxE1AdB and Adv for human IL-12 augmented the IL-12 production by 370-fold. Injecting AxE1AdB into the PANC-1 tumor of severe combined immunodeficient mice (SCID mice) resulted in marked reduction of the volume of the tumor. Moreover, injecting AxE1AdB with AxCAhIL2 into the PANC-1 tumor resulted in complete regression of the established tumors. These data suggest that RRCA, which augments the antitumor effect of a viral transgene (i.e., cytokines), may be a powerful tool for treating p53-deficient pancreatic cancer.

Adenoviridae↗
PubMed2000

Quantitative digitography (QDG): a sensitive measure of digital motor control in idiopathic Parkinson's disease.

This study introduces a new method for studying, quantitatively, the dynamics of finger movement using data obtained from sequences of key strikes on a computer-interfaced piano keyboard. We have called this quantitative digitography (QDG). This initial article introduces the method in a group of patients with Parkinson's disease and in a group of healthy subjects using simple, repetitive, alternating finger-tapping for 60 seconds. Patients with idiopathic Parkinson's disease (IPD) were studied "ON" and "OFF" dopaminergic medication before and after pallidotomy. Customized software allowed the independent analysis of key strike velocity, duration of key strike, and frequency of tapping along with a quantitative measure of the regularity of performance. Quantitative measures of the improvement in performance after medication are presented for each parameter of movement. The technique also reveals correlates of some clinical phenomena of the temporal disturbances of repetitive motion in IPD, such as fatigue, tremor, freezing, and festination. We demonstrate that the performance of 60 seconds of alternating finger tapping on a computerized keyboard yields objective measures of motor performance that are significantly different in patients with IPD "OFF" when compared with "ON" medication and when compared with healthy subjects. This is the first time that such a method has been used in the measurement of specific kinematics of digital motion in Parkinson's disease. The equipment is inexpensive and portable and the data are rapidly and easily collected, making it suitable for the outpatient setting.

Adult↗
PubMed2000

Role of lipophilicity in determining cellular uptake and antitumour activity of gold phosphine complexes.

PURPOSE: The lipophilic cation [Au(I)(dppe)2]+ [where dppe is 1,2-bis(diphenylphosphino)ethane] has previously demonstrated potent in vitro antitumour activity. We wished to determine the physicochemical basis for the cellular uptake of this drug, as well as of analogues including the 1:2 adducts of Au(I) with 1,2-bis(di-n-pyridylphosphino)ethane (dnpype; n = 2, 3 and 4), and to compare in vitro and in vivo antitumour activity. METHODS AND RESULTS: Logarithmic IC50 values for the CH-1 cell line bore a parabolic dependence on drug lipophilicity, as measured either by high-performance liquid chromatography or by n-octanol-water partition. Cellular uptake of drug, as measured by inductively coupled plasma mass spectrometry, varied by over three orders of magnitude over the series. Logarithmic uptake had a parabolic dependence on drug lipophilicity but a linear relationship to logarithmic IC50 values. Free drug concentrations were determined under the culture conditions and logarithmic free drug IC50 values and uptake rates were linearly related to lipophilicity. Uptake of drug in vivo in tissue from murine colon 38 tumours was approximately proportional to the dose administered. Host toxicity varied according to lipophilicity with the most selective compound having an intermediate value. This compound was also the most active of those tested in vivo, giving a growth delay of 9 days following daily intraperitoneal dosing (10 days) at 4 micromol kg(-1) day(-1). It was also significantly more active than another lipophilic cation, MKT-077. CONCLUSIONS: Alteration of lipophilicity of aromatic cationic antitumour drugs greatly affects cellular uptake and binding to plasma proteins. Changes in lipophilicity also affect host toxicity, and optimal lipophilicity may be a critical factor in the design of analogues with high antitumour activity.

Animals↗
PubMed2000

Placebo treatment in acute stroke trials : benefit or harm to patients?

BACKGROUND AND PURPOSE: Some stroke patients and their families express reservations about participating in trials of experimental therapies for acute stroke. Among many reasons given for this is the concern that by participating, patients may be deprived of some component of routine care. We sought to determine the effect on outcome of participating in a clinical stroke trial while being treated with placebo. METHODS: Prospective clinical information was collected for all patients admitted with acute ischemic stroke between July 1995 and July 1996. A subgroup of these patients was enrolled in a clinical trial of acute stroke therapy and had been randomly assigned to the placebo group. The control group was selected from concurrent stroke patients who were not enrolled in any clinical trial. The National Institutes of Health Stroke Scale (NIHSS) was performed on admission and on day 7 after admission. The Glasgow Outcome Scale (GOS) was also performed at discharge. Stroke severity was classified as "severe" if NIHSS was >/=9 or GOS >/=3. Group comparisons were performed with chi(2) tests. RESULTS: One hundred twenty-six patients were evaluated. Forty-seven were placebo patients, and 79 were selected as control subjects. There were no significant differences between the groups with respect to age, sex, hematocrit, blood glucose level, history of hypertension, diabetes, smoking, or initial NIHSS. In addition, there was no difference between groups in terms of the frequency of baseline stroke subtype. Among our controls, 55 patients (70%) were on antithrombotic treatment during hospitalization, whereas none of our placebo patients were on any antithrombotic treatment. For the GOS at follow-up, a good outcome was attained by 76% of the control subjects and 72% of placebo patients (not significant). A severe NIHSS (>9) at follow-up, however, was documented in 15% of controls and 59% of placebo patients (P<0.001). There was a trend toward a higher ("worse") mean follow-up NIHSS among placebo patients (mean NIHSS, 11) versus controls (mean NIHSS, 6) (P=0.09). CONCLUSIONS: Patients enrolled in the placebo arms of some acute clinical stroke trials have similar functional outcomes but more severe neurological deficits at 1 week than did a control group. These findings might be partially explained by the withholding of antithrombotic medication and the exclusion criteria inherent in most trials. Vigilance is required to ensure that all patients participating in stroke studies be guaranteed optimal known medical therapy.

Aged↗
PubMed2000

Derivation and pilot assessment of a health promotion program for Mandarin-speaking Chinese older adults.

As the percentage of older adults of diverse ethnicities increases in the United States, the call for culturally sensitive health care service strategies that target the special needs of older people grows. The present report describes methods used to adapt a health care program so that it would better meet the needs of a group of well, older Mandarin-speaking Chinese residents of Los Angeles. The specific qualitative research procedures that we used to adapt the treatment program are described, along with the particular adaptations that emerged. Additionally, outcomes from a randomized pilot experiment are presented that are consistent with the notion that the adapted program was effective in reducing health-related declines among older Mandarin-speaking men and women. The overall outcome of this project is in agreement with other reports in the health care literature that address the importance of providing culturally sensitive health care service for elders.

Aged↗
PubMed2000

[FruA, a transcription factor in Myxococus xamthus, regulates transcription of target genes in collaboration with the associated protein FruB].

Many developmental genes are regulated by FruA, a transcription factor essential for the development of Myxococus xamthus. Another protein, designated FruB, was purified from myxobacteria by its affinity to FruA. FruB could be phosphorylated by protein kinase(s) located in cell membrane. Gel shift assay showed that FruA regulates transcription of target genes in collaboration with phosphorylated FruB. This study may shed light on the molecular mechanisms of regulatory network involved in the development of Myxococus xamthus.

Bacterial Proteins↗
PubMed2000

[Changes of nitric oxide and endothelin plasma levels and effects of hormone replacement therapy in postmenopausal women].

OBJECTIVES: To investigate the changes of plasma levels of nitric oxide(NO) and endothelin (ET) when the estrogen level dropped and to assess the effects of hormone replacement therapy (HRT) on NO, ET plasma levels in postmenopausal women. METHODS: Twenty-six women with regular menses (regular mense group), twenty-eight perimenopausal women with climacteric symptoms (perimenopausal group), seventy healthy postmenopausal women (postmenopausal group) were in duded in this study. Thirty postmenopausal volunteers received oral conjugated estrogen/medroxyprogesterone acetate (post menopause group I) and twenty others took only calcium (post menopause group II) for 6 months. Plasma NO, ET, follicle-stimulation hormone (FSH) and estradiol (E2) levels were measured for all the women. RESULTS: The levels of NO were significantly lower in perimenopausal group (23.8 +/- 15.1) mumol/L and postmenopausal group (20.0 +/- 12.1) mumol/L than those of regular mense group (33.2 +/- 15.5) mumol/L (P < 0.05, P < 0.01). The mean concentrations of ET were significantly higher in both of perimenopausal (59.3 +/- 14.2) pg/L and postmenopausal groups (65.3 +/- 16.2) pg/L than those of regular mense group (51.1 +/- 15.6) pg/L (P < 0.01). Plasma NO (32.9 +/- 16.1) mumol/L and E2(47.5 +/- 12.9) pg/L values were significantly higher, and ET (52.2 +/- 12.0) pg/L values significantly lower than baselines of NO (20.3 +/- 11.1) mumol/L, E2(7.9 +/- 4.8) ng/Land ET(62.6 +/- 18.9) pg/L, respectively, in menopause group I after treatment for 6 months (P < 0.01). There was no difference in NO, ET and E2 concentrations in menopause group II before and after taking calcium for 6 month (P > 0.05). E2 had a significant positive correlation with NO and significant negative correlation with ET and FSH. CONCLUSIONS: HRT results in an increased level of NO and decreased level of ET in postmenopausal women. This may be one of the mechanisms by which HRT provides cardiovascular benefit.

Adult↗
PubMed2000

[Research on the regular pattern of Ag-NOR changes in patients with cancer].

OBJECTIVE: To correlate the relationship between rDNA transcriptional activity of CD4+ helper T cells and immunity in patients with cancer through silver stainability of nucleolus organizing regions (Ag-NORs). METHODS: The Th(CD4+) rDNA transcriptional activity was compared among patients with cancer, infectious diseases, non-cancerous non-infectious diseases through image analysis. RESULTS: Th(CD4+) rDNA transcriptional activity was decreased extremely in patients with cancer, but increased in patients with inflammation compared with normal controls. CONCLUSION: The analysis of Th(CD4+) rDNA transcriptional activity may serve as a new tumor marker for tumor diagnosis and differential diagnosis. Therefore, it may provide an innovative and reliable method for clinical cancer diagnosis.

CD4-Positive T-Lymphocytes↗
PubMed2000

[Determination of trace elements in serum of tuberculosis patients].

In order to investigate the changes of molybdenum (Mo), zinc (Zn), copper (Cu), manganese (Mn) and seleniumin (Se) level in serum of tuberculosis patients, the concentrations of Mo, Zn, Cu, Mn and Zn in serum of 30 tuberculosis patients and 30 health controls were determined by inductively coupled plasma mass spetrometry. The results showed that compared with the control group, the levels of Mo, Zn, Cu, and Se in the serum of tuberculosis patients decreased significantly (P < 0.001), but the change of Mn was insignificant (P > 0.05).

Adolescent↗
PubMed2000

[Study on the third-order nonlinear optical effect of fused-cyclic aromatic hydrocabon].

The third-order nonlinear optical susceptibility X(3), nonlinear refractive index n2 and time response property of 1,2,5,6,dibenzathracene (C22H14) and dibenzopentacene (C30H18) in fused-cyclic aromatic hydrocarbon were studied with forward degenerate four-wave mixing (DFWM). The mechanism for their larger nonlinear effect and faster time response was discussed.

English Abstract↗
PubMed2000

[Determination of chlorzoxazone and paracetamol in co-chlorzoxazone tablet by multi-wavelength linear regression method].

This paper reports that the contents of chlorzoxazone and paracetamol in the co-chlorzoxazone tablet may be determined by the multi-wavelength linear regression method. The program was edited by BASIC. The average recovery and RSD of chlorzoxazone and paracetamol were 98.67%, 0.34% and 100.05%, 0.31% (n = 5), respectively. This method is simple and rapid with satisfactory results.

Acetaminophen↗