Induction of strong cytotoxic T-lymphocyte responses to hepatitis C virus with recombinant poly-epitope in BALB/c mice.
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Animals↗
Biomedical subjects
S Ling
Publications and source records attributed to S Ling.
Clinical use of a shortened alcohol withdrawal scale in a general hospital.
BACKGROUND: Multi-item scales for monitoring alcohol withdrawal reactions have been used since the 1970s, and since 1985 we have used a modified version of the Clinical Institute Withdrawal Assessment (CIWA) in our general hospitals. This study was conducted to determine whether a shorter version of the scale would prove easier to use without loss of accuracy. METHODS: A simultaneous 'crossover' clinical audit using two hospitals. The shortened scale was developed from the existing one, and had 10 items as opposed to the previous 18. The patients were followed throughout their course and the incidences of complication, the frequency of sedation, the delay in initiating monitoring and the ease of use were recorded. RESULTS: There were 106 patients managed with the old scale and 96 with the new. The rate of complication was not different, being 16% in patients managed using the old scale and 14.5% using the new scale; the rates of sedation were 49 and 48%, respectively. Patients managed with the new scale had a shorter course with a median duration of 27.6 h compared with 40 h. The time from admission to first recording of a score was 5.4 h for the new scale and 4.8 h for the old, which is not a significant difference. Both scores were used according to instructions, but staff reported that the shortened scale was easier to use. CONCLUSIONS: We conclude that a shortened form of the CIWA alcohol withdrawal scale works as well as the original and is simple to use.
Adult↗
Assessment of the sustainability of bushmeat hunting based on dynamic bioeconomic models.
Open-access hunting is a dynamic system in which individual hunters respond to changes in system variables such as costs of hunting and prices obtained for their catch. Sustainability indices used by conservationists ignore these human processes and focus only on the biological sustainability of current offtake levels. This focus implicitly assumes that offtake is constant, says little about the actual sustainability of the system, and fails to provide any basis for predicting the impact of most feasible management interventions. A bioeconomic approach overcomes these limitations by explicitly integrating both the biological and human components of the system. We present a graphical representation of a simple bioeconomic model of bushmeat hunting and use it to demonstrate the importance of considering system dynamics when assessing sustainability. Our results show that commonly used static sustainability indices are often misleading. The best method to assess hunting sustainability is situation dependent, but characterizing supply and demand curves, even crudely, has greater potential than current approaches to provide robust predictions in the medium term.
Animals↗
The Biomolecular Interaction Network Database and related tools 2005 update.
The Biomolecular Interaction Network Database (BIND) (http://bind.ca) archives biomolecular interaction, reaction, complex and pathway information. Our aim is to curate the details about molecular interactions that arise from published experimental research and to provide this information, as well as tools to enable data analysis, freely to researchers worldwide. BIND data are curated into a comprehensive machine-readable archive of computable information and provides users with methods to discover interactions and molecular mechanisms. BIND has worked to develop new methods for visualization that amplify the underlying annotation of genes and proteins to facilitate the study of molecular interaction networks. BIND has maintained an open database policy since its inception in 1999. Data growth has proceeded at a tremendous rate, approaching over 100 000 records. New services provided include a new BIND Query and Submission interface, a Standard Object Access Protocol service and the Small Molecule Interaction Database (http://smid.blueprint.org) that allows users to determine probable small molecule binding sites of new sequences and examine conserved binding residues.
Animals↗
Widespread musculoskeletal pain and the progression of disability in older disabled women.
BACKGROUND: Widespread musculoskeletal pain is a poorly understood but common problem in older adults. Little is known about the progression of disability related to this condition. OBJECTIVE: To determine whether widespread musculoskeletal pain increases the risk for worsening disability in older women with disabilities. DESIGN: Prospective cohort study. SETTING: The Women's Health and Aging Study. PARTICIPANTS: 1002 community-dwelling women 65 years of age or older with disability. MEASUREMENTS: Widespread musculoskeletal pain was defined as pain in the upper and lower extremities and axial pain with moderate or severe pain in at least one of the three regions. Worsening disability was defined as progression from no or mild difficulty to severe difficulty or inability to perform activities of daily living (ADLs), walk one-quarter mile, or lift 10 lbs. RESULTS: At baseline, 24% of participants had widespread pain and 25% had no pain or only mild pain in a single site. Women with widespread pain were 2.5 to 3.5 times more likely to have severe difficulty with ADLs, walking, or lifting at baseline compared with women who had no or mild pain. In women without severe difficulty initially, widespread pain nearly doubled the risk for progression to severe difficulty in each of the tasks, after adjustment for age, body mass index, comorbid illness, and other confounders. CONCLUSION: Widespread musculoskeletal pain is frequent among community-dwelling older women with disability and appears to predict the progression of disability. Efforts to better understand the cause of this pain and its treatment might reduce the overall burden of disability.
Activities of Daily Living↗
Tolerance in baboon kidney transplantation with total lymphoid irradiation (TLI) and anti-CD3/CD4-idarubicin conjugates.
BACKGROUND: We previously reported the induction of transplantation tolerance by a modified wide field method of pretransplant total lymphoid irradiation (TLI), cumulative dose 800 cGy, given as 80 or 100 cGy fractions twice/week, in approximately one-third of chacma baboons receiving liver or kidney allografts (1-4) and in vervet monkeys receiving baboon kidney xenografts (5). In this study, the effects of the administration of brief courses of anti-CD3 or CD4-Idarubicin conjugates on the frequency and predictability of tolerance induction by TLI were examined. METHODS: TLI was administered pretransplant in doses of 800, 600, or 400 cGy. The conjugates were administered either after transplantation in doses of 0.25 mg/kg body weight, 3 times/week for 2 weeks, or as a single dose of 1.0 mg/kg body weight 24 hr before transplantation. RESULTS: Operational tolerance, defined as normal graft function >1 year after transplantation, was obtained in one-half of six baboons receiving the single dose of 1 mg/kg of Idarubicin conjugate pretransplant after 800 cGy of TLI and also in one of four baboons treated with 400 cGy of TLI and a single dose of anti-CD3 conjugate before transplantation. By contrast, administration of the conjugated antibodies 3 times/week for 2 weeks after transplantation prevented tolerance induction in all animals, providing further evidence for the involvement of active mechanisms, capable of inhibition by immunosuppressive agents, in tolerance induction with TLI, and of relevance to our reported clinical experience with TLI (6). CONCLUSIONS: These promising findings invite further studies with a larger number of animals and additional brief regimens of irradiation and antibody dosages and specificities.
Animals↗
Involvement of the chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase sequence His444-Arg-Glu-Arg in modulation of the bisphosphatase activity by its kinase domain.
The bisphosphatase activity of the hepatic bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is repressed by its kinase domain, and regulated by cAMP-dependent protein kinase (PKA)-catalysed phosphorylation. In the present study, the mechanism by which the bisphosphatase activity is repressed by the kinase domain and regulated by phosphorylation was investigated. We found that truncation of the C-terminus of the enzyme by 25, but not 20, amino acids dramatically enhanced the catalytic rate of the bisphosphatase, abrogated the inhibition by the kinase domain, and eliminated the effect of PKA-mediated phosphorylation on activity. In addition, mutation of His444-Arg-Glu-Arg to Ala-Ala-Glu-Ala had similar effects as the deletion. Moreover, the mutations also significantly affected the phosphorylation-mediated regulation of the kinase activity of the enzyme. Furthermore, the mutations altered the pH-dependence of the bisphosphatase, and the mutant bisphosphatases were more sensitive to modification by diethyl pyrocarbonate and guanidine-induced inactivation than the wild-type enzyme. Taken together, these results demonstrate that the sequence His444-Arg-Glu-Arg plays a critical role in repression of the bisphosphatase activity by both the N-terminal kinase domain and the C-terminal tail itself. These results also explain the activation of the bisphosphatase activity by PKA-catalysed phosphorylation, by suggesting that phosphorylation may relieve the inhibitory effect of the kinase domain that is mediated by the three basic residues in this sequence.
Amino Acid Sequence↗
Binding of ATP to the fructose-2,6-bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase leads to activation of its 6-phosphofructo-2-kinase.
To understand the mechanism by which the activity of the 6-phosphofructo-2-kinase (6PF-2K) of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is stimulated by its substrate ATP, we studied two mutants of the enzyme. Mutation of either Arg-279, the penultimate basic residue within the Walker A nucleotide-binding fold in the bisphosphatase domain, or Arg-359 to Ala eliminated the activation of the chicken 6PF-2K by ATP. Binding analysis by fluorescence spectroscopy using 2'(3')-O-(N-methylanthraniloyl)-ATP revealed that the kinase domains of these two mutants, unlike that of the wild type enzyme, showed no cooperativity in ATP binding and that the mutant enzymes possess only the high affinity ATP binding site, suggesting that the ATP binding site on the bisphosphatase domain represents the low affinity site. This conclusion was supported by the result that the affinity of ATP for the isolated bisphosphatase domain is similar to that for the low affinity site in the wild type enzyme. In addition, we found that the 6PF-2K of a chimeric enzyme, in which the last 25 residues of chicken enzyme were replaced with those of the rat enzyme, could not be activated by ATP, despite the fact that the ATP-binding properties of this chimeric enzyme were not different from those of the wild type chicken enzyme. These results demonstrate that activation of the chicken 6PF-2K by ATP may result from allosteric binding of ATP to the bisphosphatase domain where residues Arg-279 and Arg-359 are critically involved and require specific C-terminal sequences.
Adenosine Triphosphate↗
Epithelioid hemangioma of bone.
Although no specific radiographic appearance has emerged to date for the epithelioid subtype of hemangioma, these lesions most typically exhibit well-defined osteolysis. Other relatively common features include surrounding sclerosis, cortical expansion and cortical destruction. We present a case of epithelioid hemangioma of the spine with an unusual radiological appearance which to our knowledge has not previously been reported: diffuse sclerosis of the involved vertebral body. The diffuse sclerosis seen in this case resembles the osteosclerotic process seen not only in benign entities such as subacute and chronic osteomyelitis, but also in malignant lesions such as osteoblastic metastatic disease and lymphoma.
Adult↗
Estrogen inhibits mechanical strain-induced mitogenesis in human vascular smooth muscle cells via down-regulation of Sp-1.
OBJECTIVE: The cellular basis of the cardioprotective effects of estrogen are largely unknown. An inhibitory effect on vascular smooth muscle (VSM) growth has been proposed. We examined the effect of 17beta-estradiol (E2) on mechanical strain-induced mitogenesis in human fetal VSM cells. METHODS AND RESULTS: Cells were grown on fibronectin-coated plates with silicone-elastomer bottoms, and exposed to cyclic mechanical strain (60 cycles/min), with and without E2 (1 nmol/l), for 48 h. [3H]-Thymidine incorporation was measured during the last 6 h. Strain induced 1.5-2 fold increases in DNA synthesis that were attenuated by antibodies to platelet-derived growth factor (PDGF) AA and BB. Strain also induced increases both in mRNA and protein levels of Sp-1, a transcription factor that binds to the PDGF-A gene promoter site. E2 attenuated strain-induced mitogenesis, and also increases in mRNA and protein levels of Sp-1. The estrogen receptor (ER) antagonist ICI 182,780 (100 nmol/l) reversed the inhibitory effect of E2 on strain-induced increases in DNA synthesis and Sp-1 protein. RT-PCR analysis showed presence of both ER-alpha and -beta in these cells. CONCLUSIONS: Estrogen inhibits strain-induced mitogenesis in human VSM cells via an ER mediated process involving down-regulation of the transcription factor Sp-1.
Cell Culture Techniques↗
LFA-1 and ICAM-1 antibody-idarubicin conjugates separately prolong murine cardiac allograft survival.
Drug antibody conjugates can enhance the activity of monoclonal antibodies (MoAb) and idarubicin-MoAb conjugates have led to tolerance induction with antibodies which are inactive when used alone. It has been reported that, in mice, antibodies to ICAM-1 and LFA-1 have to be used together to induce tolerance to cardiac allografts; here we show that these monoclonal antibodies, conjugated to idarubicin, can lead to tolerance induction to cardiac allografts when used alone.
Animals↗
Enhanced activity of a large conductance, calcium-sensitive K+ channel in the presence of Src tyrosine kinase.
Large conductance, calcium-sensitive K(+) channels (BK(Ca) channels) contribute to the control of membrane potential in a variety of tissues, including smooth muscle, where they act as the target effector for intracellular "calcium sparks" and the endothelium-derived vasodilator nitric oxide. Various signal transduction pathways, including protein phosphorylation can regulate the activity of BK(Ca) channels, along with many other membrane ion channels. In our study, we have examined the regulation of BK(Ca) channels by the cellular Src gene product (cSrc), a soluble tyrosine kinase that has been implicated in the regulation of both voltage- and ligand-gated ion channels. Using a heterologous expression system, we observed that co-expression of murine BK(Ca) channel and the human cSrc tyrosine kinase in HEK 293 cells led to a calcium-sensitive enhancement of BK(Ca) channel activity in excised membrane patches. In contrast, co-expression with a catalytically inactive cSrc mutant produced no change in BK(Ca) channel activity, demonstrating the requirement for a functional cSrc molecule. Furthermore, we observed that BK(Ca) channels underwent direct tyrosine phosphorylation in cells co-transfected with BK(Ca) channels and active cSrc but not in cells co-transfected with the kinase inactive form of the enzyme. A single Tyr to Phe substitution in the C-terminal half of the channel largely prevented this observed phosphorylation. Given that cSrc may become activated by receptor tyrosine kinases or G-protein-coupled receptors, these findings suggest that cSrc-dependent tyrosine phosphorylation of BK(Ca) channels in situ may represent a novel regulatory mechanism for altering membrane potential and calcium entry.
Animals↗
Determination of Guan-Fu Base A, a new anti-arrhythmic, in human plasma by gas chromatography and electron-capture detection.
A gas chromatographic-electron capture detection (GC-ECD) method has been developed for determining Guan-Fu Base A (GFA), an experimental anti-arrhythmic, in human plasma. The method was based on one-step liquid-liquid extraction with toluene and chemical derivatization with pentafluoropropionic anhydride followed by GC-ECD. The derivatives of GFA and metoprolol (Met, internal standard) were confirmed by gas chromatography-mass spectrometry (GC-MS) to be dipentafluoropropionyl-GFA and dipentafluoropropionyl-Met. The method was linear over the concentration ranges of 0.1-20.0 and 1.0-30.0 microg/ml with the detection limit of 0.05 microg/ml at S/N=5. The intra- and inter-assay precisions were less than 6 and 10%, and accuracy 99.70+/-3.30 and 97.60+/-5.99%, respectively. The absolute recoveries were 81.88, 77.35, 80.79 and 83.85% for GFA at concentrations of 0.5, 1.0, 5.0 and 14.0 microg/ml and 88.24% for Met at 3.0 microg/ml, respectively.
Adult↗
Asymptomatic peripheral arterial disease is independently associated with impaired lower extremity functioning: the women's health and aging study.
BACKGROUND: We report the implications of asymptomatic lower extremity peripheral arterial disease (PAD) for lower extremity functioning among participants in the Women's Health and Aging Study, an observational study of disabled women > or = 65 years of age living in and around Baltimore. METHODS AND RESULTS: The ankle brachial index (ABI) and measures of upper and lower extremity functioning were measured among study participants. Of 933 women with ABI < or =1. 50, 328 (31%) [corrected] had an ABI <0.90, consistent with PAD. Sixty-three percent of PAD participants had no exertional leg pain. Among participants without exertional leg pain, lower ABI levels were associated with slower walking velocity, poorer standing balance score, slower time to arise 5 times consecutively from a seated position, and fewer blocks walked per week, adjusting for age, sex, race, cigarette smoking, and comorbidities. ABI was not associated independently with measures of upper extremity functioning. CONCLUSIONS: Asymptomatic PAD is common and is independently associated with impaired lower extremity functioning. In addition to preventing cardiovascular morbidity and death, further study is warranted to identify effective interventions to improve functioning among the growing number of men and women with asymptomatic PAD.
Aged↗
Mitochondrial Ca(2+)homeostasis in the regulation of apoptotic and necrotic cell deaths.
Using distinct models of apoptosis and necrosis, we have investigated the effect of mitochondrial Ca(2+)(Ca(m)) homeostasis in the regulation of cell death in neuroblastoma cells as well as cardiac myocytes. The steady state level of Ca(m)was determined as the FCCP-releasable Ca(2+). Culturing cells with low concentration of extracellular Ca(2+)(Ca(o)) or with EGTA triggered an early reduction in both the Ca(m)store and the membrane potential (DeltaPsi(m)). This was followed by the detection of cytochrome c release, caspase activation, and apoptosis. Inhibitors of the mitochondrial permeability transition pore such as cyclosporin A and Bcl-2 blocked the release of Ca(m)and inhibited apoptosis. In contrast, mitochondrial Ca(2+)overload resulted in necrotic cell death. Culturing cells in the presence of excess Ca(o)led to increased Ca(m)load together with a decrease of DeltaPsi(m)that reached maximum at 1 h, with necrosis occurring at 2 h. While the decline of Ca(m)and DeltaPsi(m)was a coupled reaction for apoptosis, this relationship was uncoupled during necrosis. Clonazepam, a relatively specific inhibitor of the mitochondrial Na/Ca exchanger, was able to protect the cells from necrosis by reducing Ca(m)overload. Importantly, combination of clonazepam and cyclosporin showed a cooperative effect in further reducing the Ca(m)overload and abolished cell death. The data imply the participation of Ca(m)homeostasis in the regulation of apoptosis and necrosis.
Animals↗
The difference in the carboxy-terminal sequence is responsible for the difference in the activity of chicken and rat liver fructose-2,6-bisphosphatase.
The fructose-2,6-bisphosphatase domain of the bifunctional chicken liver enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase shares approximately 95% amino acid sequence homology with that of the rat enzyme. However, these two enzymes are significantly different in their phosphatase activities. In this report, we show that the COOH-terminal 25 amino acids of the two enzymes are responsible for the different enzymatic activities. Although these 25 amino acids are not required for the phosphatase activity, their removal diminishes the differences in the activities between the two enzymes. In addition, two chimeric molecules (one consisting of the catalytic core of the chicken bisphosphatase domain and the rat COOH-terminal 25 amino acids, and the other consisting of most of the intact chicken enzyme and the rat COOH-terminal 25 amino acids) showed the same kinetic properties as the rat enzyme. Furthermore, substitution of the residues Pro456Pro457Ala458 of the chicken enzyme with GluAlaGlu, the corresponding sequence in the rat liver enzyme, yields a chicken enzyme that behaves like the rat enzyme. These results demonstrate that the different bisphosphatase activities of the chicken and rat liver bifunctional enzymes can be attributed to the differences in their COOH-terminal amino acid sequences, particularly the three residues.
Amino Acid Sequence↗
Correlation of genetic polymorphism of cytochrome P4502D6 with dextromethorphan oxidative metabolism in Chinese.
OBJECTIVE: To determine the genetic mechanism of dextromethorphan oxidative polymorphism in Chinese subjects. METHODS: CYP2D6 genotype was analyzed by polymerase chain reaction (PCR) and Hph I restriction fragment length polymorphism (RFLP) techniques in 119 healthy Chinese subjects. RESULTS: The gene frequency of CYP2D6*10B was 58.4%, including 13(10.9%) of homozygous wild type(w/w), 33 (27.7%) of homozygous mutant(m/m), and 73(61.3%) of heterozygous genotypes(m/w). Twenty-nine subjects out of 42 intermediate metabolizers(70%) of dextromethorphan were homozygous for CYP2D6*10B. One poor metabolizer subject also showed an m/m genotype. Besides, 10 Chinese subjects were tested and excluded for the presence of any of the six mutant alleles associated with poor metabolism of CYP2D6 in Caucasians. CONCLUSION: The CYP2D6*10B allele containing the C(188)--> T mutation is the major cause of CYP2D6 polymorphism in relation to diminished dextromethorphan oxidative capacity in Chinese subjects.
Adolescent↗
Mechanical strain increases PDGF-B and PDGF beta receptor expression in vascular smooth muscle cells.
Cyclic mechanical strain causes proliferation of vascular smooth muscle cells, mediated in part by platelet-derived growth factor (PDGF). We examined the effect of cyclic strain on expression of PDGF-B and the PDGF beta receptor. Neonatal rat vascular smooth muscle cells were exposed to 1 hertz cyclic strain on silicone elastomer plates. PDGF-B mRNA increased after 6 h of strain. In cells transfected with a PDGF-B promoter chloramphenicol acetyl transferase construct (psisCAT 6A), activity increased by 12-fold following 12 h of strain. Two neutralizing antibodies to the PDGF beta receptor both reduced strain-induced [(3)H]thymidine incorporation by 50%. Expression of the PDGF beta receptor protein increased 1.8-fold following 24 h of strain. During strain, PDGF beta receptor expression was not significantly altered by neutralizing antibodies to PDGF-B. Thus, both PDGF-B and the PDGF beta receptor are induced by cyclic mechanical strain and both contribute to cell proliferation in response to strain.
Animals↗