Biomedical subjects

C Ding

Publications and source records attributed to C Ding.

At least 19 recordsLinked to original sources

PubMed2005

Factors affecting progression of knee cartilage defects in normal subjects over 2 years.

OBJECTIVES: Cartilage defects are present in subjects with knee osteoarthritis (OA). Although they are often present in healthy subjects, there is little data on the natural history of cartilage defects. The aim of this study was to examine the change in cartilage defects over 2 yr and to identify factors associated with this change. METHODS: One hundred and twenty-four healthy subjects underwent magnetic resonance imaging of their dominant knee at baseline and follow-up. Cartilage defects were scored (0-4) at five sites. Bone size was determined at medial and lateral tibial plateau and patella. Height, weight, body mass index and physical activity were measured by standard protocols. RESULTS: Eighty-six subjects completed the study. The mean cartilage defect score of each tibiofemoral compartment increased over time. However, medial and lateral tibiofemoral defect score decreased in 5% of the subjects. Cartilage defects were more likely to progress in males than females in each individual compartment (P<0.001 for medial tibiofemoral, P=0.005 for lateral tibiofemoral and P=0.01 for patellar cartilage). Baseline cartilage defect score was negatively associated with the progression of cartilage defects in each compartment (all P<0.001). CONCLUSION: Although knee cartilage defects progressed over time in the majority of normal subjects, those of the highest severity tended to regress. Male gender and baseline cartilage defect score were the main factors associated with the progression of cartilage defects. Larger studies will be required to identify factors associated with the progression and regression of lesions.

Body Mass Index↗

PubMed2005

The clinical correlates of articular cartilage defects in symptomatic knee osteoarthritis: a prospective study.

OBJECTIVES: To determine whether articular cartilage defects are associated with cartilage loss and joint replacement in subjects with symptomatic knee osteoarthritis (OA). METHODS: One hundred and seventeen subjects with symptomatic knee OA underwent magnetic resonance imaging of their dominant knee at baseline and 2 yr later. Cartilage defects were identified as prevalent (defect score > or =2) in each knee compartment. Occurrence of joint replacement by 4 yr was documented. RESULTS: Cartilage defects were present in 81% of medial, 64% of lateral tibiofemoral compartments and 55% of patellar cartilages. Annual patellar cartilage loss was highest in those with defects compared with no defects (5.5% vs 3.2%, P = 0.01). Tibial cartilage loss was not associated with defects in the medial (4.6% vs 5.8%, P = 0.42) or lateral (4.7% vs 6.5%, P = 0.21) tibial cartilages. Higher total cartilage defect scores (8-15) were associated with a 6.0-fold increased risk of joint replacement over 4 yr compared with those with lower scores (2-7) (95% confidence interval 1.6, 22.3), independently of potential confounders. CONCLUSIONS: Articular cartilage defects are associated with disease severity in knee OA and predict patellar cartilage loss and knee replacement.

Aged↗

PubMed2005

Ion excitation in a linear quadrupole ion trap with an added octopole field.

Modeling of ion motion and experimental investigations of ion excitation in a linear quadrupole trap with a 4% added octopole field are described. The results are compared with those obtained with a conventional round rod set. Motion in the effective potential of the rod set can explain many of the observed phenomena. The frequencies of ion oscillation in the x and y directions shift with amplitude in opposite directions as the amplitudes of oscillation increase. Excitation profiles for ion fragmentation become asymmetric and in some cases show bistable behavior where the amplitude of oscillation suddenly jumps between high and low values with very small changes in excitation frequency. Experiments show these effects. Ions are injected into a linear trap, stored, isolated, excited for MS/MS, and then mass analyzed in a time-of-flight mass analyzer. Frequency shifts between the x and y motions are observed, and in some cases asymmetric excitation profiles and bistable behavior are observed. Higher MS/MS efficiencies are expected when an octopole field is added. MS/MS efficiencies (N(2) collision gas) have been measured for a conventional quadrupole rod set and a linear ion trap with a 4% added octopole field. Efficiencies are chemical compound dependent, but when an octopole field is added, efficiencies can be substantially higher than with a conventional rod set, particularly at pressures of 1.4 x 10(-4) torr or less.

Ions↗

PubMed2005

Association between age and knee structural change: a cross sectional MRI based study.

OBJECTIVE: To describe the associations between age, knee cartilage morphology, and bone size in adults. METHODS: A cross sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61) was studied. Knee measures included a cartilage defect five site score (0-4 respectively) and prevalence (defect score of > or =2 at any site), cartilage volume and thickness, and bone surface area and/or volume. These were determined at the patellar, medial, and lateral tibial and femoral sites using T(1)weighted fat saturation MRI. Height, weight, and radiographic osteoarthritis (ROA) were measured by standard protocols. RESULTS: In multivariate analysis, age was significantly associated with knee cartilage defect scores (beta = +0.016 to +0.073/year, all p<0.01) and prevalence (OR = 1.05-1.10/year, all p<0.05) in all compartments. Additionally, age was negatively associated with knee cartilage thickness at all sites (beta = -0.013 to -0.035 mm/year, all p<0.05), and with patellar (beta = -11.5 microl/year, p<0.01) but not tibial cartilage volume. Lastly, age was significantly positively associated with medial and lateral tibial surface bone area (beta = +3.0 to +4.7 mm(2)/year, all p<0.05) and patellar bone volume (beta = +34.4 microl/year, p<0.05). Associations between age and tibiofemoral cartilage defect score, cartilage thickness, and bone size decreased in magnitude after adjustment for ROA, suggesting these changes are directly relevant to OA. CONCLUSION: The most consistent knee structural changes with increasing age are increase in cartilage defect severity and prevalence, cartilage thinning, and increase in bone size with inconsistent change in cartilage volume. Longitudinal studies are needed to determine which of these changes are primary and confirm their relevance to knee OA.

Adult↗

PubMed2004

Neuroradiological findings in glutaric aciduria type I (glutaryl-CoA dehydrogenase deficiency).

This article summarizes the magnetic resonance imaging features of glutaric aciduria type I (GA I) based on the cases presented at the 3rd International Workshop on Glutaryl-CoA Dehydrogenase Deficiency together with a review of previously reported neuroimaging characteristics of GA I. Previous reports have focused on characteristic findings, such as basal ganglia injury and frontotemporal atrophy or hypoplasia, subdural effusions and white-matter disease. Most of these findings have been demonstrated in symptomatic children, i.e. after manifestation of acute encephalopathic crises. In contrast, prospective investigations in presymptomatically diagnosed children are rare. Since more recent investigations have highlighted CNS changes in patients without encephalopathic crises, systematic prospective investigations of neuroradiological findings in this disease are indispensable for a better understanding of this disease. Based on these findings a suggestion for a MRI protocol is presented, supporting a standardized evaluation of patients with GA I.

Amino Acid Metabolism, Inborn Errors↗

PubMed2004

Genetic mechanisms of knee osteoarthritis: a population based case-control study.

OBJECTIVE: To compare subjects who had at least one parent with a total knee replacement for severe primary knee osteoarthritis with age and sex matched controls who had no family history of knee osteoarthritis DESIGN: Population based case-control study of 188 matched pairs (mean age 45 years, range 26 to 60). METHODS: Articular cartilage volume and bone size were determined at the patella and at the medial tibial and lateral tibial compartments by processing images acquired using T1 weighted, fat saturated magnetic resonance imaging. Radiographic osteoarthritis (ROA) was assessed from a standing semiflexed radiograph scored for joint space narrowing and osteophytosis. Knee pain was assessed by questionnaire. Height, weight, body mass index (BMI), lower limb muscle strength, and endurance fitness were measured by standard protocols. RESULTS: Compared with the controls, index offspring had higher BMI (27.8 v 26.0 kg/m(2), p = 0.02), weaker lower limb muscles (127 v 135 kg, p = 0.006), more knee pain (47% v 22%, p<0.001), and greater medial tibial bone area (17.6 v 17.1 cm(2), p = 0.01). With the exception of BMI, these differences persisted in multivariate analysis. There was a non-significant trend to higher cartilage volume at tibial sites and increased ROA in the offspring in the total and subgroup analyses, but no difference in height and endurance fitness. CONCLUSIONS: BMI, muscle strength, knee pain, and medial tibial bone area, but not cartilage volume, appear to play a role in the genetic regulation and development of knee osteoarthritis.

Adult↗

PubMed2003

Sex differences in knee cartilage volume in adults: role of body and bone size, age and physical activity.

OBJECTIVE: To test the hypothesis that sex differences in knee cartilage volume may be mediated through body and bone size, age and/or physical activity. METHODS: A cross-sectional convenience sample of 372 subjects (males 43%; mean age 45 yr, range 26-61) was studied. Articular cartilage volumes and bone size were determined at the patella, medial and lateral tibia by processing images acquired in the sagittal plane using T1-weighted fat saturation magnetic resonance imaging. Height, weight, physical activity (lower limb muscle strength, endurance fitness and questionnaire items) and radiographic osteoarthritis (ROA) were measured. RESULTS: Gender explained 33-42% of the variation in knee cartilage volumes (all P < 0.001). Males had 33-42% higher cartilage volume than females at all sites. In the whole group, the magnitude of sex differences decreased to 8-18% after adjustment for body height, weight and bone size, but remained significant (all P < 0.05). Further adjustment for physical activity had no effect on the sex differences. The sex differences in cartilage volume were greater in those aged over 50 compared with those aged under 50 (P < 0.05 for age-sex interaction at all sites) and were independent of ROA. CONCLUSIONS: Men have substantially higher knee cartilage volumes than women. These sex differences appear to be mediated in part by body and bone size but a significant amount remains unexplained. Furthermore, the differences become more marked over the age of 50 yr suggesting that both cartilage development and cartilage loss in later life contribute to sex differences in cartilage volume. Further longitudinal studies in large samples will be required to confirm these findings.

Adult↗

PubMed2003

Serum lysophosphatidic acid concentrations measured by dot immunogold filtration assay in patients with acute myocardial infarction.

In this study the relation between lysophosphatidic acid (LPA) and myocardial infarction was investigated, the typical and simplified methods for measuring serum LPA concentration by dot immunogold filtration assay (DIFA) based on a polyclonal antibody to LPA were developed, and serum LPA concentrations were measured in 31 patients with acute myocardial infarction (AMI) and 12 controls (blood donors) by DIFA. Serum LPA levels were raised more than twofold 8 h after the onset of AMI. Maximal elevation (10.43 mg/L) was found at 48-72 h following onset and remained higher than the control concentration (1.66 mg/L) 7 days after AMI. The rise in serum LPA concentration in AMI patients suggests that LPA might be involved in AMI-related pathophysiology in the cardiovascular system. The simplified DIFA developed in the present study for measuring serum LPA concentration is convenient and highly sensitive.

Adolescent↗

PubMed2003

Effects of hyperglycemic and normoglycemic cerebral ischemia on phosphorylation of c-jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK).

Transient global cerebral ischemia leads to delayed neuronal cell death in the hippocampal CA1, caudate putamen and neocortex. If preischemic hyperglycemia exists, the same duration of ischemia recruits additional brain structures, such as dentate gyrus to become damaged. The objective of the present study is to determine whether activation of mitogen-activated protein kinases (MAPKs) plays a role in hyperglycemia-mediated ischemic neuronal damage. Using phopho-specific antibodies against c-jun NH2-terminal kinase (JNK) and p38 MAPK, we studied activation of these two MAPKs in ischemia-vulnerable neocortex and ischemia-resistant dentate gyrus in rats subjected to 15 min of forebrain ischemia and followed by 0.5, 1 and 3 hr of recirculation under normo- and hyperglycemic conditions. The results showed that levels of phosphorylated JNK increased in both normo- and hyperglycemic brains following blood reperfusion for 0.5 hr and persisted up to 3 hr in the neocortex but not in the dentate gyrus, implying JNK may play a role in mediating neuronal cell death after ischemia. However, since hyperglycemia did not further increase phospho-JNK, JNK may not contribute to the detrimental effect of hyperglycemia on neuronal cell death. The amount of phospho-p38 was not altered by ischemia under both normo- and hyperglycemic conditions, suggesting that p38 MAPK may not play a major role in mediating neuronal damage in these two structures.

Animals↗

PubMed2002

Quantitative analysis of (styrene/acrylonitrile/methyl methacrylate) co-polymer systems by infrared resonance spectroscopy.

A detailed careful analysis of the infrared resonance (IR) spectra of polystyrene (PSt), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) and their co-mixtures were performed. Through this study the absorption peak area to weight ratios as well as working curves were obtained to test for their reliability as well as their suitability. Satisfactory results were achieved and these working curves were then used to measure the polymerized components of binary and ternary co-polymers. By investigating the acquired data we conclude that the monomer preferential polymeric sequence is St > MMA > AN. A quantitative method to measure P (St/AN/MMA) concentrations by IR spectroscopy is proposed in this work.

Acrylonitrile↗

PubMed2001

Treatment with a growth hormone secretagogue in a model of developing heart failure: effects on ventricular and myocyte function.

BACKGROUND: Exogenous administration of growth hormone (GH) and subsequently increased production of insulin-like growth factor-1 can influence left ventricular (LV) myocardial growth and geometry in the setting of congestive heart failure (CHF). This study determined the effects of an orally active GH secretagogue (GHS) treatment that causes a release of endogenous GH on LV function and myocyte contractility in a model of developing CHF. METHODS AND RESULTS: Pigs were randomly assigned to the following treatment groups: (1) chronic rapid pacing at 240 bpm for 3 weeks (n=11); (2) chronic rapid pacing and GHS (CP-424,391 at 10 mg x kg(-1) x d(-1), n=9); and (3) sham controls (n=8). In the untreated pacing CHF group, LV fractional shortening was reduced (21+/-2% versus 47+/-2%) and peak wall stress increased (364+/-21 versus 141+/-5 g/cm(2)) from normal control values (P:<0.05). In the GHS group, LV fractional shortening was higher (29+/-2%) and LV peak wall stress lower (187+/-126 g/cm(2)) than untreated CHF values (P:<0.05). With GHS treatment, the ratio of LV mass to body weight increased by 44% from untreated values. Steady-state myocyte velocity of shortening was reduced with pacing CHF compared with controls (38+/-1 versus 78+/-1 microm/s, P:<0.05) and was increased from pacing CHF values with GHS treatment (55+/-7 microm/s, P:<0.05). CONCLUSIONS: The improved LV pump function that occurred with GHS treatment in this model of CHF was most likely a result of favorable effects on LV myocardial remodeling and contractile processes. On the basis of these results, further studies are warranted to determine the potential role of GH secretagogues in the treatment of CHF.

Animals↗

PubMed2001

Apatite formed on the surface of plasma-sprayed wollastonite coating immersed in simulated body fluid.

Wollastonite coatings on titanium alloys substrates were prepared by plasma spraying and incubated in simulated body fluids for different periods to investigate the nucleation and growth of apatite on their surface. Surface structural changes of the specimens were analyzed by XRD and IR technologies. SEM and EDS were used to observe surface morphologies and determine the composition of wollastonite coatings before and after immersion in simulated body fluid. The changes in the concentrations of calcium, silicon and phosphorus in the simulated body fluids due to the immersion of the specimens were measured by inductively coupled plasma atomic emission spectroscopy. The results obtained showed that hydroxycarbonate apatite can be formed on the surface of the coating soaked in SBF for 1 day. With longer immersion periods, the coating surface was covered by hydroxycarbonate apatite, which indicated that the wollastonite coating possesses good bioactivity.

Alloys↗

PubMed2001

Familial isolated hypoparathyroidism caused by a mutation in the gene for the transcription factor GCMB.

Hypoparathyroidism is characterized by hypocalcemia, hyperphosphatemia, and absent or markedly reduced circulating concentrations of parathyroid hormone. The transcription factor GCMB is predominantly, if not exclusively, expressed in parathyroid cells and is critical for development of the parathyroid glands in mice. Thus, in the present study we examined the GCMB gene, mapped to 6p23-24, as a candidate for isolated hypoparathyroidism. We defined the boundaries of the five exons of the human GCMB gene and then identified a large intragenic mutation in the GCMB genes of the proband of an extensive kindred with isolated hypoparathyroidism. Her parents and several other unaffected relatives were heterozygous for the mutation. Despite an absence of any history of consanguinity, microsatellite analysis showed shared genotypes that flanked the GCMB gene over a span of 5 cM, suggesting that both of the proband's GCMB alleles had been derived from a single common ancestor. Analysis of additional, unrelated cases did not disclose the same mutation. We conclude that homozygous loss of function of the GCMB gene impairs normal parathyroid gland embryology and is responsible for isolated hypoparathyroidism in a subset of patients with this disease.

Alleles↗

PubMed2001

Neuronal nitric oxide synthase and the autonomic innervation of the mouse lacrimal gland.

PURPOSE: To determine the expression patterns of the vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS) in the pterygopalatine ganglion (PPG) and the exorbital lacrimal gland of normal mice. METHODS: Mouse PPG and lacrimal glands were processed for single- and double-labeled indirect immunofluorescence studies. Slides were examined with conventional fluorescence microscopy and confocal laser scanning microscopy. RESULTS: All the somata in the PPG expressed both VAChT and nNOS immunoreactivity (IR). The postganglionic axons within the ganglion showed less VAChT-immunoreactive intensity than that seen in the somata, whereas nNOS IR was almost undetectable. In the lacrimal gland, nNOS-positive nerve bundles and fibers were observed to be associated with tear-collecting ducts, blood vessels, and acini. Some nNOS-positive punctate elements appeared to be distributed among acini. Many nerve fibers were VAChT immunoreactive and a small number of fibers were TH immunoreactive in the gland. Most of the VAChT-positive fibers and some of the TH-positive nerves displayed nNOS IR. CONCLUSIONS: The expression of nNOS in cells of the PPG and in lacrimal gland nerves suggests that NO may play a role in modulating tear production. The site of action may include the PPG, ducts, blood vessels, acini, nerve fibers, and myoepithelial cells within the gland. NO may modulate parasympathetic and/or sympathetic synaptic transmission or by acting directly on lacrimal gland components. The interaction between NO-ergic and the conventional autonomic input illustrates the complexity of the innervation pattern of the mouse lacrimal gland.

Animals↗

PubMed2001

[The role of neutrophils and interleukin-8 in pathogenesis of asthma].

OBJECTIVE: To investigate the role of neutrophils and interleukin-8 (IL-8) in pathogenesis of asthma. METHODS: Pulmonary function and bronchial provocation test were performed to identify and evaluate asthma. Superoxide anion O(2)(-.) generation of peripheral blood neutrophils, IL-8 and malondialhyde (MDA) levels in plasma and induced sputum were measured. RESULTS: The O(2)(-.) generation [(20.9 +/- 5.1) nmol] of peripheral blood neutrophils from moderate-severe asthmatics were significantly higher than that [(15.2 +/- 4.2) nmol] from mild asthmatics (P < 0.01), in which that was still significantly higher than that [(11.3 +/- 2.4) nmol] from normal subjects (P < 0.05). The O(2)(-.) generation of peripheral blood neutrophils had significantly negative correlation with PD(20)FEV(1) (r = -0.693, P < 0.05). The levels of IL-8 [(585 +/- 75) ng/L, (791 +/- 103) ng/L] and MDA levels [(6.3 +/- 1.6) mmol/L, (21.8 +/- 6.3) mmol/L] in plasma and induced sputum from unstable asthmatics were higher than those [(227 +/- 54) ng/L, (322 +/- 95) ng/L and (5.4 +/- 1.0) mmol/L, (15.1 +/- 5.6) mmol/L] from stable asthmatics (P < 0.01), more over, in the latter group, they were still significantly higher than those (188 +/- 46) ng/L, (224 +/- 51) ng/L and [(4.1 +/- 0.4) mmol/L, (9.5 +/- 4.2) mmol/L] from normal subjects (P < 0.05). The levels of MDA in the induced sputum from stable asthmatics showed a negative correlation with PD(20)FEV(1) (r = -0.708, P < 0.01). The levels of IL-8 in the induced sputum showed a positive correlation with percentage of neutrophils in the induced sputum (r = 0.838, P < 0.01). CONCLUSIONS: IL-8 and oxygen free radicals generated by neutrophils might participate in development of airway inflammation and airway hyperresponsiveness in asthma.

Adult↗

PubMed2000

A 5-month, randomized, placebo-controlled trial of galantamine in AD. The Galantamine USA-10 Study Group.

OBJECTIVE: To investigate the efficacy and tolerability of galantamine, using a slow dose escalation schedule of up to 8 weeks, in 978 patients with mild to moderate AD. METHODS: A 5-month multicenter, placebo-controlled, double-blind trial. Following a 4-week placebo run-in, patients were randomized to one of four treatment arms: placebo or galantamine escalated to final maintenance doses of 8, 16, or 24 mg/day. Outcome measures included the cognitive subscale of the AD Assessment Scale (ADAS-cog), the Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC-plus), the AD Cooperative Study Activities of Daily Living inventory, and the Neuropsychiatric Inventory. Standard safety evaluations and adverse event monitoring were carried out. RESULTS: After 5 months, the galantamine-placebo differences on ADAS-cog were 3.3 points for the 16 mg/day group and 3.6 points for the 24 mg/day group (p < 0.001 versus placebo, both doses). Compared with placebo, the galantamine 16- and 24-mg/day groups also had a significantly better outcome on CIBIC-plus, activities of daily living, and behavioral symptoms. Treatment discontinuations due to adverse events were low in all galantamine groups (6 to 10%) and comparable with the discontinuation rate in the placebo group (7%). The incidence of adverse events in the galantamine groups, notably gastrointestinal symptoms, was low and most adverse events were mild. CONCLUSIONS: Galantamine 16 and 24 mg/day significantly benefits the cognitive, functional, and behavioral symptoms of AD as compared with placebo. Slow dose escalation appears to enhance the tolerability of galantamine, minimizing the incidence and severity of adverse events.

Activities of Daily Living↗

PubMed2000

Pharmacokinetics of levamisole in cancer patients treated with 5-fluorouracil.

PURPOSE: To investigate the pharmacokinetics of levamisole and a metabolite, p-hydroxylevamisole in patients with colorectal cancer treated with 5-fluorouracil (5-FU). METHODS: Following an intravenous bolus dose of 5-FU, 20 patients with colorectal cancer received oral doses of 50 mg levamisole every 8 h for 3 days. Immediately after the last dose, blood and urine samples were collected over at least an 8-h period. Samples were assayed for levamisole and p-hydroxylevamisole by GC/MS. The levamisole plasma and urine data were subjected to pharmacokinetic analysis using NONMEM software. RESULTS: Substantial interpatient variability was observed in the levamisole plasma concentration-time curves. Patients with cardiovascular or gastrointestinal complications demonstrated altered absorption of levamisole. Pharmacokinetic parameter values for levamisole were similar to those obtained previously in healthy subjects and other cancer patients. CONCLUSIONS: There is no evidence that the pharmacokinetics of levamisole are altered by 5-FU administered immediately prior to levamisole administration. The relationship between the substantial intersubject variability in levamisole plasma concentration-time curves and clinical outcome following 5-FU/levamisole adjuvant chemotherapy should be examined.

Adjuvants, Immunologic↗

PubMed2000

Bond strength of plasma-sprayed hydroxyapatite/Ti composite coatings.

One of the most important clinical applications of hydroxyapatite (HA) is as a coating on metal implants, especially plasma-sprayed HA coating applied on Ti alloy substrate. However, the poor bonding strength between HA and Ti alloy has been of concern to orthopedists. In this paper, an attempt has been made to enhance the bonding strength of HA coating by forming a composite coating with Ti. The bioactivity of the coating has also been studied. HA/Ti composite coatings were prepared via atmospheric plasma spraying on Ti-6Al-4V alloy substrates. The bond strength evaluation of HA/Ti composite coatings was performed according to ASTM C-633 test method. X-ray diffractometer and scanning electron microscopy were applied to identify the phases and the morphologies of the coatings. The bioactivity of HA/Ti composite coating was qualified by immersion of coating in simulated body fluid (SBF). The obtained results revealed that the addition of Ti to HA improved the bonding strength of coating significantly. In the SBF test, the coating surface was covered by carbonate-apatite, which was testified by X-ray photoelectron spectroscope, indicating good bioactivity for HA/Ti composite coating. The bioactivity of the coating has not been reduced by the addition of Ti.

Alloys↗