Biomedical subjects

L Ding

Publications and source records attributed to L Ding.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Evaluation of saliva ferning test in diagnosis of Sjögren's syndrome].

OBJECTIVE: To evaluate saliva ferning test in (SFT) diagnosis of xerostomia in patients with Sjögren's syndrome (SS). METHODS: Dried samples of freshly produced saliva from 78 patients diagnosed as SS according to european community criteria and 80 healthy controls were examined by light microscopy. The crystallization was classified into 4 types according to the ferning phenomenon: uniformity, branching, spreading and integrity (type I normal and type II, III, IV abnormal). Then, the 78 patients underwent labial salivary gland biopsy. According to Tarpley's classification of labial gland biopsy, > or = 2+ was considered positive. RESULTS: (a) The sensitivity and specificity of SFT were 89.74% (70/78) and 83.75% (67/80) respectively. (b) Abnormal SFT was observed in 70/78 (89.74%) of SS and in 13/80 (16.25%) of normal controls. The differences of SFT in SS patients versus normal controls were significant (P < 0.01). (c) The sensitivity of SFT and labial gland biopsy had no significant differences (P > 0.05) as diagnostic tests in SS. CONCLUSIONS: SFT was valuable as a diagnostic test in patients suspective of SS.

Adolescent↗

PubMed2001

[Study on the phase I metabolites of phenoprolamine hydrochloride in rat bile by LC/DAD/MSD].

AIM: To study the phase I metabolites of phenoprolamine hydrochloride (DDPH) in rat bile. METHODS: DDPH was administered i.p. to bile duct-cannulated rats. Bile samples were collected before administration and up to 12 h after administration. After being treated with beta-glucuronidase, the bile samples were purified and enriched with C-18 SPE columns, and then were analyzed by LC/DAD/MSD. The samples containing synthesized reference standards of DDPH metabolite 1-(2, 6-dimethylphenoxy)-2-(3-methoxy-4-hydroxyphenylethylamino)-propane (M1), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3, 4-methoxy-phenylethylamino)-propane (M2), 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3,4- methoxyphenylethylamino)-propane (M3), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3-hydroxy-4- methoxyphenylethylamino)-propane (M4), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2- (3-hydroxy-4-methoxyphenylethylamino)-propane (M5) and 1-(2,6-dimethyl-4-hydroxyphenoxy)-2-(3-methoxy-4- hydroxyphenylethylamino)-propane (M6) were analyzed by LC/DAD/MSD under identical conditions. RESULTS: The retention times, UV spectra, molecular weights and production spectra (obtained by collision-induced dissociation) of the apparent ions of peak A, B, C, D, E and F in the total ion chromatogram of DDPH treated rat bile sample were consistent with those of M1, M2, M3, M5, M4 and M6, respectively. CONCLUSION: M1, M2, M3, M4, M5 and M6 were identified as the phase I metabolites of DDPH in the rat.

Animals↗

PubMed2001

[An abzyme to catalytize the deiodination of thyroxine].

AIM: To mimic an important family of selenoenzymes in organism-thyroxine (T4) deiodinases and prepare a selenium-containing abzyme catalyzing deiodination of T4. METHODS: A anti-T4 monoclonal antibody was generated by hybridoma methodology and converted into a selenium-containing abzyme by the method of chemical modification. The catalytic activity of the enzyme was measured by RIA method. RESULTS: The abzyme displayed a marked activity of catalyzing deiodination of T4 and a higher specificity to the substrate T4 than that of natural enzyme, and the double reciprocal plots of the initial rates of T3 formation vs. T4 concentration yielded a family of parallel lines. The catalytic activity could be sensitively inhibited by 6-propyl-2-thiouracil (PTU), a competitive inhibitor for dithiothreitol (DTT). CONCLUSION: An abzyme with the diodination activity was first prepared and the reaction mechanism of the enzyme was bisubstrate ping-pong one.

Animals↗

PubMed2001

[Study on the phase II metabolites of phenoprolamine hydrochloride in rat bile by LC/DAD/MSD].

AIM: To study the phase II metabolites of phenoprolamine hydrochloride (DDPH) in rat bile. METHODS: DDPH was administered by i.p. to bile duct-cannulated rats. Bile samples were collected before drug administration and up to 12 h after drug administration. After being purified and enriched with C-18 SPE columns the rat bile samples were analyzed by LC/DAD/MSD to identify the peaks of phase II metabolites. The fractions of phase II metabolites were prepared by HPLC and treated with beta-glucuronidase, and then were purified and enriched with C-18 SPE columns and analyzed by LC/DAD/MSD. The corresponding reference standards of DDPH phase I metabolites were analyzed by LC/DAD/MSD under identical conditions. RESULTS: The peaks M7, M8 and M9 in the chromatograms of rat bile samples were the phase II metabolites of DDPH and the enzymatic hydrolysates of M7, M8 and M9 were 1-(2, 6-dimethyl-4-hydroxyphenoxy)-2-(3, 4-methoxyphenylethylamino)-propane (M3), 1-(2, 6-dimethyl-3-hydroxyphenoxy)-2-(3, 4-methoxyphenylethylamino)-propane (M2) and 1-(2,6-dimethylphenoxy)-2-(3-methoxy-4-hydroxyphenylethyl-amino)-propane (M1) respectively. CONCLUSION: beta-1-O-[3,5-dimethyl-4-[-2-methyl-2-(3,4-dimethoxy-phenylethylamino)- ethoxy]-phenyl]-glucuronic acid (M7, glucuronide of M3), beta-1-O-[2, 4-dimethyl-3-[2-methyl-2-(3, 4-dimethoxy-phenylethylamino)-ethoxy]-phenyl]-glucuronic acid (M8, glucuronide of M2) and beta-1-O-[2-methoxy-4-[1-methyl-2-(2, 6-dimethylphenoxy)-ethylamino-ethyl]-phenyl]-glucuronic acid (M9, glucuronide of M1) were the phase II metabolites of DDPH in rat bile.

Animals↗

PubMed2000

Omega -crystallin of the scallop lens. A dimeric aldehyde dehydrogenase class 1/2 enzyme-crystallin.

While many of the diverse crystallins of the transparent lens of vertebrates are related or identical to metabolic enzymes, much less is known about the lens crystallins of invertebrates. Here we investigate the complex eye of scallops. Electron microscopic inspection revealed that the anterior, single layered corneal epithelium overlying the cellular lens contains a regular array of microvilli that we propose might contribute to its optical properties. The sole crystallin of the scallop eye lens was found to be homologous to Omega-crystallin, a minor crystallin in cephalopods related to aldehyde dehydrogenase (ALDH) class 1/2. Scallop Omega-crystallin (officially designated ALDH1A9) is 55-56% identical to its cephalopod homologues, while it is 67 and 64% identical to human ALDH 2 and 1, respectively, and 61% identical to retinaldehyde dehydrogenase/eta-crystallin of elephant shrews. Like other enzyme-crystallins, scallop Omega-crystallin appears to be present in low amounts in non-ocular tissues. Within the scallop eye, immunofluorescence tests indicated that Omega-crystallin expression is confined to the lens and cornea. Although it has conserved the critical residues required for activity in other ALDHs and appears by homology modeling to have a structure very similar to human ALDH2, scallop Omega-crystallin was enzymatically inactive with diverse substrates and did not bind NAD or NADP. In contrast to mammalian ALDH1 and -2 and other cephalopod Omega-crystallins, which are tetrameric proteins, scallop Omega-crystallin is a dimeric protein. Thus, ALDH is the most diverse lens enzyme-crystallin identified so far, having been used as a lens crystallin in at least two classes of molluscs as well as elephant shrews.

Aldehyde Dehydrogenase↗

PubMed2000

Inhibition of cell migration by 24-kDa fibroblast growth factor-2 is dependent upon the estrogen receptor.

The single-copy gene for fibroblast growth factor-2 (FGF-2) encodes for multiple forms of the protein with molecular masses of 24, 22.5, 22, and 18 kDa. We reported previously that the 24-22-kDa FGF-2 forms inhibit the migration of endothelial and MCF-7 cells by 50% and 70%, respectively. Here we show that this inhibition of migration is mediated by the estrogen receptor (ER). We have found that depletion of the receptor in either cell line abrogates the inhibitory activity of 24-kDa FGF-2 while re-introduction of the ER into deficient cells once again promotes the inhibitory response. To determine whether exposure to 24-kDa FGF-2 resulted in the activation of the estrogen receptor, 3T3 cells were cotransfected with estrogen receptor cDNA and an estrogen regulatory element-luciferase gene reporter construct and treated with 24- and 18-kDa FGF-2. The high molecular weight form stimulated luciferase activity 5-fold while 18-kDa FGF-2 at the same concentration had no effect. Treatment of ER-positive MCF-7 cells transfected with the reporter construct only showed the same results. Inclusion of the pure estrogen antagonist ICI 182,780 blocked the increase in luciferase activity by 24-kDa FGF-2, further indicating that the response was estrogen receptor dependent. Expression of dominant negative FGF receptor 1 inhibited ER activation, indicating that this was the cell surface receptor mediating the effect. Although growth factor-dependent activation of the ER was reported to require mitogen-activated protein kinase-induced phosphorylation at Ser(118) in COS and HeLa cells, this mechanism is not involved with the activation by 24-kDa FGF-2. These results suggest that the addition of 55 amino acids to the amino-terminal end of 18-kDa FGF-2 by alternative translation alters FGF-2 function and allows for the activation of a second signaling pathway involving the estrogen receptor.

3T3 Cells↗

PubMed2000

Concurrent Parkinson tremors.

1. Concurrent resting and postural tremors of patients with idiopathic Parkinson's disease were monitored using transducers responding to angular velocity of rotation. Spectra and correlation functions were calculated for each pair of records. 2. When concurrent tremor spectra share indistinguishable fundamental frequencies, have statistically significant peaks in their coherence spectra at those fundamental frequencies, and show significant peaks in their cross-correlation functions near zero delay, they are classified as linearly dependent. When such tremor records are superimposed, their phase-locked behaviour is evident. 3. Pairs of correlated concurrent tremors, of varying duration, have been observed in both hands, both feet and in either hand and the contralateral or ipsilateral foot. Correlated tremors may be concurrent with other tremors that are independent. We hypothesize that correlated Parkinson tremors arise from one or more common (and possibly unilateral) central sources.

Aged↗

PubMed2000

Association of several small heat-shock proteins with reproductive tissues in the nematode Caenorhabditis elegans.

Immunohistochemical data on 10 of the 14 small heat-shock (smHSPs) proteins in fourth larval stage and adult Caenorhabditis elegans show that the tissues expressing the greatest number of smHSPs are vulva (HSP12s, HSP43 and, under stress, HSP16s) and spermatheca (HSP12s, HSP25, HSP43 and, under stress, HSP16s). HSP43 is also expressed in male tail structures, and following heat-shock HSP16s are expressed in spermatids and spermatozoa.

Aging↗

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↗