Biomedical subjects

W Meng

Publications and source records attributed to W Meng.

At least 19 recordsLinked to original sources

PubMed2007

Systemic lupus erythematosus: a genetic epidemiology study of 695 patients from China.

Our purpose was to explore potential genetic models for systemic lupus erythematosus (SLE) and analyze genetic epidemiologic characteristics of SLE in a Chinese population. Data for 695 patients with SLE were obtained by using a uniform questionnaire. Patients, clinical characteristics and their family history were analyzed using software. A complex segregation analysis was conducted to propose potential genetic models for SLE. The mean +/- SD age of onset were 30.2 +/- 10.5 years and mean time to progression to SLE was 32.5 +/- 44.4 months. The most frequent initial manifestations were malar rash (61.3%). During the evolution of the disease, the main clinical features were arthritis in 73.6% of our patients, followed by malar rash (68.1%), and renal involvement (56.7%). As the first symptom, the late-onset group (onset of disease beyond the age of 50 years) less often showed malar rash (45% vs. 63.4% in the early-onset group; p = 0.001). There were no significant differences in the other cumulative clinical symptoms between late-onset and early-onset group, except for a lower prevalence of malar rash, photosensitivity and alopecia and a higher prevalence of mucosal ulcers in the late-onset group. A positive family history of SLE was obtained in 50 patients (7.2%). There were no statistical differences in clinical characteristics between familial SLE and sporadic SLE patients. The heritability of SLE was 43.6%, the genetic model of SLE could be polygenetic model and major gene mode is the best fitted one. SLE could be a multifactorial disease with polygenetic model.

Adolescent↗

PubMed2006

Uptake and metabolism of novel biodegradable poly (glycerol-adipate) nanoparticles in DAOY monolayer.

A useful route for the development of antitumour therapies is by creating improved methods for delivering therapeutic agents to tumour cells or subcellular compartments and increasing retention of drugs within target cells. In this study, we have characterized nanoparticle (NP) uptake and metabolism by DAOY cells, a human medulloblastoma cell line. NPs were formed from a novel polymer, poly (glycerol-adipate) (PGA), containing Rhodamine B Isothiocyanate (RBITC) as a fluorescent marker. It was observed that the cellular uptake of NPs depends on the incubation time and the concentration of NPs in the culture medium. The studies of retention and metabolism of NPs within cells indicated that 1) faster degradation of NPs within cells compared with that in cell culture medium in vitro; 2) a small fraction of NPs were recycled back to the outside of cell, whereas most NPs entered endosomes and lysosomes; and 3) recycled NPs were re-taken up in the following 2 h incubation time. These studies thus suggested that PGA NPs could be used for localising therapeutic agents into cells, and could provide prolonged drug effects because of their long sustained release in physiological conditions and their rapid release when taken up into cells.

Antineoplastic Agents↗

PubMed2005

Risk factors for goiter in a previously iodine-deficient region.

OBJECTIVE: Little information exists from formerly iodine-deficient areas regarding gender-specific risk factors for goiter and their synergisms. The aim of the present study was to investigate such gender-specific risk factors and their interactions in a large population-based sample. METHODS AND RESULTS: The Study of Health in Pomerania (SHIP) comprised 4310 randomly selected participants, aged 20 - 79 years. SHIP was performed in a previously iodine-deficient region. Data from 3915 participants with no known thyroid disorders were analyzed. Goiter was determined by thyroid ultrasound. Sociodemographic characteristics, smoking and alcohol drinking habits, marital status, education level, urine thiocyanate concentrations, and specifically in women, parity and previous or current use of oral contraceptives and hormone replacement therapy, were considered as candidate risk factors for multivariable statistical tests. Only two variables, an advanced age and current smoking, were independently associated with an increased risk for goiter in both genders. Analyses further revealed specific risk factor profiles for goiter which were different among men, pre- and postmenopausal women. CONCLUSION: We conclude that besides previous iodine deficiency, other risk factors for goiter exist which differ between gender. Among the avoidable risk factors, current smoking was strongly associated with the risk of goiter in men and women. These findings should influence activities which are intended to prevent thyroid disease.

Adult↗

PubMed2005

Mental and physical complaints in thyroid disorders in the general population.

OBJECTIVE: To test the hypothesis that untreated overt and subclinical thyroid disorders and autoimmune thyroiditis (AIT) are associated with mental and physical complaints in the general population. METHOD: A total of 3790 participants from the Study of Health in Pomerania (SHIP) with no known thyroid disorders were analyzed concerning their thyroid function (TSH, FT3, FT4), autoantibodies (TPO-Ab), their thyroid structure and size and their mental and physical complaints (Zerssen Complaint Scale). RESULTS: Overt hyperthyroidism (prevalence: 0.4%) was associated with a significantly lower total complaint-score than euthyroid subjects. Subjects with overt hypothyroidism (0.5%), subclinical hypothyroidism (0.7%), or subclinical hyperthyroidism (1.6%) were not different from controls in their total complaints. Females with AIT showed higher scores of tachycardia and anxiety independent from their thyroid function. CONCLUSION: In non-patient samples, hyperthyroidism is associated with positive effects on self-rated mental and physical health. AIT may be associated with negative effects on health also in euthyroid subjects.

Adult↗

PubMed2005

Morphology and metabolism of hepatocytes microencapsulated with acrylic terpolymer-alginate using gelatin and poly(vinyl alcohol) as extracellular matrices.

Microcapsules with good mechanical stability were prepared using an appropriate mixture of alginate and acrylic terpolymer. It was found from the microscopic observation that the microcapsules had a porous structure with interconnected pores, with a size of 50-150 nm. The results of the permeability experiment of microcapsules using FITC-dextrans showed that the capsule had a molecular mass cut-off of 120 kDa. The hepatocytes encapsulated in both alginate and acrylic terpolymer with gelatin and PVA rapidly aggregated in the core. The aggregated cells showed high albumin synthesis and ammonia removal, suggesting good metabolic function.

Acrylates↗

PubMed2004

[Medical treatment of nodular goiter].

An optimal supply of iodine--150-200 microg/day--has not yet been secured in all regions and in all phases of life. The appreciable diminishment in thyroid gland mass in children and adolescents is, however, indicative of an improvement in this situation. In elderly persons, however, prophylactic measures do not result in struma or nodule regression. Nodules are found in some 40% of women and 28% of men older than 45. Medical treatment of nodular goiter is aimed at achieving a reduction in size or preservation of the status quo. Depending on the size of the goiter, iodine-deficiency goiter is treated with iodine or a combination of iodine and levothyroxine. In view of the pathogenesis and the marginal alimentary lack that still persists, there are no adequate arguments for L-thyroxine monotherapy of uncomplicated iodine-deficiency goiter.

Adolescent↗

PubMed2004

Measurement of the negative muon anomalous magnetic moment to 0.7 ppm.

The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 ppm (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement for the negative muon. The result a(mu(-))=11 659 214(8)(3) x 10(-10) (0.7 ppm), where the first uncertainty is statistical and the second is systematic, is consistent with previous measurements of the anomaly for the positive and the negative muon. The average of the measurements of the muon anomaly is a(mu)(exp)=11 659 208(6) x 10(-10) (0.5 ppm).

Journal Article↗

PubMed2004

Replacement therapy with levothyroxine plus triiodothyronine (bioavailable molar ratio 14 : 1) is not superior to thyroxine alone to improve well-being and cognitive performance in hypothyroidism.

OBJECTIVES: There is evidence from recent controlled clinical studies that replacement therapy of hypothyroidism with T4 in combination with a small amount of T3 may improve the well-being of the patients. As the issue is still the subject of controversial discussion, our study was assigned to confirm the superiority of a physiological combination of thyroid hormones (absorbed molar ratio 14 : 1) over T4 alone with regard to mood states and cognitive functioning. DESIGN AND PATIENTS: After a run-in period with the T4 study medication for 4 weeks, a controlled, randomized, double-blind, two-period (each 12 weeks), cross-over study without washout between the treatment periods was performed in 23 hypothyroid patients (three males, 20 females, age 23-69 years, 21 subjects after surgery/radioiodine, two with autoimmune thyroiditis) to compare the effects of the previous individual T4 dose (100-175 micro g) with a treatment in which 5% of the respective T4 dose was substituted by T3. MEASUREMENTS: Standard hormonal characteristics and standardized psychological tests to quantify mood and cognitive performance were measured after the run-in period and at the end of each treatment period. In 12 subjects, the concentration-time profiles of fT3 and fT4 were compared after the last administration of the respective study medication. TSH, fT3 and fT4 were measured with immunological assays. CLINICAL RESULTS: Replacement therapy with T4 and T4/T3 was not different in all steady-state hormonal, metabolic and cardiovascular characteristics except for TSH, which was more suppressed after T4/T3. The efficacy of replacement therapy with the T4/T3 combination was not different from the T4 monotherapy with regard to all psychological test scores describing mood and cognitive functioning of the patients. Mood was even significantly impaired by the T4/T3 combination in eight subjects, with TSH < 0.02 mU/l, compared to patients with normal TSH (Beck Depression Inventory: 8.25 +/- 5.01 vs. 4.07 +/- 5.60, P = 0.026). PHARMACOKINETIC RESULTS: The area under the concentration-time curve (AUC(0-8h)) of fT3 was significantly higher after T4/T3 compared to the T4 monotherapy (42.8 +/- 9.03 pmol x h/l vs. 36.3 +/- 8.50 pmol x h/l, P < 0.05) and was significantly correlated to serum TSH (r(s) = -0.609, P < 0.05). After T4/T3, patients with a history of Graves' disease or autoimmune thyroiditis had significantly higher serum trough levels of fT3 whereas the fT4 concentrations were significantly lower in patients with a nonautoimmune background. CONCLUSION: Replacement therapy of hypothyroidism with T4 plus T3 does not improve mood and cognitive performance compared to the standard T4 monotherapy. There is even a higher risk of signs of subclinical hyperthyroidism associated with impaired well-being of the patients, which is clearly caused by significant fluctuations in the steady-state fT3 serum concentrations.

Adult↗

PubMed2003

[Hereditary medullary thyroid carcinoma--genotype-phenotype characterization].

BACKGROUND AND OBJECTIVE: Hereditary medullary thyroid carcinoma (MTC) is caused by germline mutations of the RET proto-oncogene. A genotype - phenotype correlation has been established, showing clustering of mutations in exons 10 and 11 in classical MEN 2 A syndrome, in exon 16 codon 918 in MEN 2 B syndrome and in exons 13-15 in familial MTC. A line of evidence suggested that the development and the aggressiveness of MTC in the different cancer syndromes is variable. Aim of this study was to compare the phenotype of exon 13-15 mutations with that of exon 11 mutation and possibly draw therapeutical consequences. PATIENTS AND METHODS: We compared the phenotype of 47 patients with mutations in exon 13-15 with 66 patients with exon 11, codon 634 mutation, the classical MEN2A. Patients were further subdivided as index and screening patients. RESULTS: Mean age of 19 index patients with codon 790, 791, 804 or 891 mutation was significant higher compared with 18 index patients with codon 634 mutation (mean age at diagnosis 50+/-12 years; range 30-69 y vs mean age 31+/-9 years; range 17-49 y), tumor stage at operation was favourable (C-cell hyperplasia n = 1; stage I n = 8; II n = 3; III n = 2; IV n = 2; no operation n = 1; no information n = 2 vs stage I n = 3; stage II n = 6; stage III n = 4, no information n =5), cure rate was better (56 % vs 38 %) and the death rate was lower (n = 2 vs n = 4). In screening patients no differences concerning the age, tumor stage, cure and death rate between patients with exons 13-15 and codon 634 mutations were seen. CONCLUSIONS: MTC in patients with exon 790, 791, 804, 891 mutations displayed a late onset and an indolent course compared to codon 634 mutation, this has to be taken into account when recommending timing and extent of prophylactic surgery.

Adolescent↗

PubMed2002

Measurement of the positive muon anomalous magnetic moment to 0.7 ppm.

A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm).

Journal Article↗

PubMed2001

The relationship between apoptosis of endplate chondrocytes and aging and degeneration of the intervertebral disc.

STUDY DESIGN: Apoptosis in cervical intervertebral disc cells and cartilaginous endplate cells was examined by the nick end labeling (TUNEL) technique during the process of natural aging and in a mouse experimental spondylosis model. OBJECTIVES: To determine the role of apoptosis in aging and degeneration of intervertebral discs by monitoring chronologic changes in the quantity and localization of apoptotic cells. SUMMARY OF BACKGROUND DATA: Apoptosis occurs within human intervertebral discs, but little is known about the pathologic significance of this process. On the other hand, the cartilaginous endplate is known to decrease in thickness and to disappear with aging and degeneration. The cause of this age-related change remains unclear. METHODS: A mouse spondylosis model was prepared via surgical resection of the posterior spinal element in 12 mice to examine the experimentally induced spondylosis process. Eighteen naturally aged mice were also used to examine the influence of aging. Paraffin-embedded midsagittal sections of the cervical spine were obtained 2, 3, 6, and 12 months after surgery in the spondylosis model and in the age-matched naturally aged mice, as well as in 4-week-old and 18-month-old naturally aged mice. Sections were stained with hematoxylin and eosin, safranin-O, and the TUNEL procedure. The number of apoptotic cells and vital cells were counted in the cartilaginous endplate of the intervertebral disc excluding the growth cartilage, and the degree of disappearance of the cartilaginous endplate was evaluated. RESULTS: Apoptosis, particularly noticeable in the cartilaginous endplate, increased with age and resulted in a marked decrease in cell density. Subsequently, the structure of the cartilaginous endplate began to disappear. Apoptosis was more evident and the structure of the cartilaginous endplate began to disappear more rapidly in the surgically treated group than in the naturally aged group. CONCLUSIONS: TUNEL-positive cells in the cartilaginous endplate increased with age, with destruction of the cartilaginous endplate after apoptosis (TUNEL-positive cell death). The application of the spondylosis model increased the incidence of apoptosis preceding the development of spondylosis. This suggests that apoptosis plays a role in the age-related changes seen in the cartilaginous endplate of the intervertebral disc and in the experimentally induced spondylosis process.

Aging↗

PubMed2001

[Electrophsiological study of rabbits with axonal form Guillain-Barre syndrome].

OBJECTIVE: To investigate the electrophysiological changes of common pheroneal nerve in rabbit model of axonal form of Guillain-Barre syndrome (GBS). METHODS: Lipopolysaccaride (LPS) was inoculated into six rabbits. Three of them got GBS and three remained healthy. The motor nerve conduction velocity of common peroneal nerve, compound muscle action potential, and latency of F wave were determined, and electromyography of anterior tibial muscle was made in the 3 rabbits modal of axonal form GBS, the 3 rabbits without symptom after inoculation of LPS, and 8 control rabbits. RESULTS: The three rabbits with axonal form GBS showed normal motor nerve conduction velocity and normal latency of F waves, and remarkably reduced compound muscle action potential amplitudes. Needle electromyography of anterior tibial muscle showed fibrillations and positive sharp waves. CONCLUSION: The electrophysiological characters of rabbits with axonal form GBS are consistent with those of patients with axonal form GBS. Electrophysiology plays an important role in diagnosing axonal form GBS.

Action Potentials↗

PubMed2001

UP element-dependent transcription at the Escherichia coli rrnB P1 promoter: positional requirements and role of the RNA polymerase alpha subunit linker.

The UP element stimulates transcription from the rrnB P1 promoter through a direct interaction with the C-terminal domain of the RNA polymerase alpha subunit (alphaCTD). We investigated the effect on transcription from rrnB P1 of varying both the location of the UP element and the length of the alpha subunit interdomain linker, separately and in combination. Displacement of the UP element by a single turn of the DNA helix resulted in a large decrease in transcription from rrnB P1, while displacement by half a turn or two turns totally abolished UP element-dependent transcription. Deletions of six or more amino acids from within the alpha subunit linker resulted in a decrease in UP element-dependent stimulation, which correlated with decreased binding of alphaCTD to the UP element. Increasing the alpha linker length was less deleterious to RNA polymerase function at rrnB P1 but did not compensate for the decrease in activation that resulted from displacing the UP element. Our results suggest that the location of the UP element at rrnB P1 is crucial to its function and that the natural length of the alpha subunit linker is optimal for utilisation of the UP element at this promoter.

Base Sequence↗

PubMed2001

Precise measurement of the positive muon anomalous magnetic moment.

A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x 10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value.

Journal Article↗

PubMed2001

Implications for familial hypercholesterolemia from the structure of the LDL receptor YWTD-EGF domain pair.

The low-density lipoprotein receptor (LDLR) is the primary mechanism for uptake of cholesterol-carrying particles into cells. The region of the LDLR implicated in receptor recycling and lipoprotein release at low pH contains a pair of calcium-binding EGF-like modules, followed by a series of six YWTD repeats and a third EGF-like module. The crystal structure at 1.5 A resolution of a receptor fragment spanning the YWTD repeats and its two flanking EGF modules reveals that the YWTD repeats form a six-bladed beta-propeller that packs tightly against the C-terminal EGF module, whereas the EGF module that precedes the propeller is disordered in the crystal. Numerous point mutations of the LDLR that result in the genetic disease familial hypercholesterolemia (FH) alter side chains that form conserved packing and hydrogen bonding interactions in the interior and between propeller blades. A second subset of FH mutations are located at the interface between the propeller and the C-terminal EGF module, suggesting a structural requirement for maintaining the integrity of the interdomain interface.

Amino Acid Motifs↗

PubMed2001

[Diagnosis of hyperthyroidism].

The clinical signs and symptoms of the patient are the background for further examination procedures. A dysfunction of the thyroid gland can be safely excluded when the TSH level is within the normal range. A hyperthyroidism can be proven when TSH is suppressed and T3 and T4 levels, respectively, are elevated. However, the concentrations of T3, T4 (inclusive free T3 and free T4) and TSH are not only dependent on the thyroid status, but also on various extrathyroidal influences. Therefore awareness of accompanying diseases and of medications is necessary in order to avoid errors of interpretation. Different forms of hyperthyroidism have to be distinguished. The differentiation between Graves' disease and the functional autonomy (toxic nodular goiter) is of practical importance. Several methods--apart from precise clinical examination--are helpful. When Graves' disease is suspected TSH-receptor- and TPO-antibodies should be measured and an ultrasound obtained. When an autonomy is suspected, a szintigraphy as well as ultrasound should be undertaken. The laboratory methods are of high precision and sensitivity. There use is dependent on the clinical diagnostic problem, which also determines the extend and expenditure of the diagnostic procedures. These considerations are necessary also for economical reasons.

Diagnosis, Differential↗

PubMed2001

[Complex segregation analysis of systemic lupus erythematosus].

OBJECTIVE: To explore the genetic model of systemic lupus erythematosus(SLE). METHODS: Complex segregation analysis was performed by using statistical analysis for genetic epidemiology-REGTL(SAGE-REGTL). The genetic model and gene frequency were estimated. 300 pedigrees with SLE were collected from 300 patients as probands. RESULTS: The complex segregation analysis found the genetic model of SLE to be additive,the gene frequency 0.336. The authors believe the possibility of some different modes coexisting under different circumstances. The genetic effect on young man is stronger than that on old one. CONCLUSION: This study suggests that the genetic mode of SLE could be the major gene trait, and additive mode is the best fitted one.

Adolescent↗

PubMed2001

[Composting process of municipal solid waste with high effective complex microbial community].

The effects of high effective complex microbial community (MECMC) in a combination composting process of municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, organic matter, the carbon, nitrogen ration (C/N). Composting was performed under such conditions: The ratio of MSW:sewage:sawdust:composting of 45:25:15:15 (W/W) and organic matter of 60%, total N of 1.4%, total P of 0.69%, total K of 1.25%, original moisture of 58.5%, original ratio of C/N of 30, aration flow of 0.8 L/min.kg(volatile organic matter). The rates of adding HECMC to treatment 1, treatment 2 and treatment 3 were 2%, 3%, 5% respectively. Control experiment added 3% inactive HECMC. The day of MSW and sludge mature in control experiment, treatment 1, treatment 2 and treatment 3 were 30, 24, 18 and 12, respectivly. This indicated HECMC were effective to compose organic matter and speedup composting change into humus. There are many active bacteria in composting which are favorable for soil.

Bacteria↗