Biomedical subjects

M Zhang

Publications and source records attributed to M Zhang.

At least 37 records · Page 2Linked to original sources

PubMed2006

The impact of malocclusion and its treatment on quality of life: a literature review.

AIM: The aim of this paper is to review the literature relating to the impact of malocclusion, and the treatment of malocclusion, on physical, social and psychological health (i.e. quality of life, QoL). DESIGN: English-language papers, including cross-sectional studies, retrospective and prospective longitudinal studies, randomized controlled trials, and reviews and meta-analyses were reviewed to determine the impact of malocclusion and its treatment on QoL. RESULTS: Malocclusion and its treatment can affect physical health in terms of pain (e.g. temporomandibular disorders, and dental and gingival trauma), speech and mastication. In terms of psychological health, malocclusion and its treatment is reported to affect self-concept. Socially, malocclusion and its treatment can affect perceived attractiveness by others, social acceptance and perceived intelligence. However, the evidence is conflicting owing to differences in study designs, population's studied and methods of assessment of psychical, social and psychological health. CONCLUSION: Much controversy exists about the impact of malocclusion and its treatment on QoL. There is a need for a more comprehensive and rigorous assessment of the impact of malocclusion and its treatment on QoL, employing standardized, valid and reliable data collection instruments.

Humans↗

PubMed2006

Neuromedin U in the paraventricular and arcuate hypothalamic nuclei increases non-exercise activity thermogenesis.

Brain neuromedin U (NMU) has been associated with the regulation of both energy intake and expenditure. We hypothesized that NMU induces changes in spontaneous physical activity and nonexercise activity thermogenesis (NEAT) through its actions on hypothalamic nuclei. We applied increasing doses of NMU directly to the paraventricular (PVN) and arcuate hypothalamic nuclei using chronic unilateral guide cannulae. In both nuclei, NMU significantly and dose-dependently increased physical activity and NEAT. Moreover, NMU increased physical activity and NEAT during the first hour of the dark phase, indicating that the reduction of sleep is unlikely to account for the increased physical activity seen with NMU treatment. As a positive control, we demonstrated that paraventricular NMU also significantly decreased food intake, as well as body weight. These data demonstrate that NMU is positively associated with NEAT through its actions in the PVN and arcuate nucleus. In co-ordination with its suppressive effects on feeding, the NEAT-activating effects of NMU make it a potential candidate in the combat of obesity.

Animals↗

PubMed2006

Delayed spinocerebellar ataxia in transgenic mice expressing mutant ubiquitin.

Spinocerebellar ataxia type 1 (SCA1) is an incurable neurodegenerative disease resulting from loss of Purkinje neurones within the cerebellum. The ubiquitin proteasome pathway (UPP) has been implicated in SCA1 but the role of proteolysis in the disease is still poorly understood. To further investigate this issue in vivo, genetic crosses were performed between an established mouse model of SCA1 and novel strains expressing elevated levels of wild type or mutant isoforms of ubiquitin. The K48R mutant isoform of ubiquitin (a dominant negative inhibitor of proteolysis) was found to significantly delay the deterioration of Purkinje neurones as evidenced by behavioural, morphological, and molecular indicators. This delay was accompanied by stabilization of p300/CBP, transcriptional mediators whose abundance and activity would otherwise decline in the course of the SCA1 disease, and persistence of protein kinase C gamma (PKCgamma), a protein involved in Purkinje cell dendritic development that is mutated in one form of spinocerebellar ataxia. Whereas the stabilization of p300/CBP was found to occur at the post-translational level the modulation of PKCgamma was at the level of transcription. These results are consistent with transcriptional dysregulation as a key mechanism in neurodegeneration through loss of p300/CBP. Further, the results suggest that the UPP is a potentially useful target for the development of novel therapies for the treatment of neurodegenerative disease.

Animals↗

PubMed2006

Anti-p97/VCP antibodies: an autoantibody marker for a subset of primary biliary cirrhosis patients with milder disease?

We previously reported that 12.5% of primary biliary cirrhosis (PBC) sera reacted with a 95 kDa cytosol protein (p95c) that was subsequently identified as a p97/valosin-containing protein (VCP). The clinical features and course of the six anti-p97/VCP-positive PBC patients with Scheuer's stage 1 and 2 liver biopsies were monitored for an average of 15 years. This group was compared with 50 PBC patients that did not have detectable anti-VCP. Autoantibodies to a full-length recombinant p97/VCP were assayed by immunoprecipitation. All six PBC patients with anti-VCP had antibodies to the mitochondrial pyruvate dehydrogenase complex-E2 antigen as measured by an addressable laser bead immunoassay. The first was a male with no evidence of liver failure that died of cerebral infarction at the age of 85. The second was a 73-year-old female with Hashimoto's thyroiditis who has remained clinically stable without ursodeoxycolic acid (UDCA) treatment. Although the third had no HCV antibodies, he developed hepatocellular carcinoma at the age of 76 and died of renal failure at 78. The fourth was a 50-year-old female who remained clinically stable during follow-up and the fifth with Hashimoto's thyroiditis and stable liver function following UCDA treatment. The sixth was a male patient presenting a mild clinical course. The clinical course of these patients was in contrast to the 50 comparison group PBC patients who did not have anti-p97/VCP. As the six PBC patients with anti-p97/VCP antibodies had slowly progressive liver disease and no mortality related to autoimmune liver disease, our observations suggest that this autoantibody might be an indicator of a favourable prognosis.

Adenosine Triphosphatases↗

PubMed2006

Effect of pregnancy on the pharmacokinetics of metformin.

AIMS: To determine the effects of pregnancy on metformin pharmacokinetics. METHODS: Seven women with Type 2 diabetes mellitus taking metformin throughout pregnancy were studied on two occasions, once at 28-36 weeks gestation and once at least 8 weeks postpartum. Serum metformin concentrations were determined across a dosing interval using high-performance liquid chromatography. The areas under the serum concentration-time curve from 0 to 4 h post-dose (AUC0-4) and 0 to 8 h post-dose (AUC0-8) where possible, were compared in the pregnant and non-pregnant state. RESULTS: Metformin concentrations were lower in pregnancy in six subjects, with a mean (95% CI) AUC0-4 that was 69% (53.6, 84.8) of the postpartum value. The AUC0-4 of one subject was higher in pregnancy at 142% of the postpartum value. Overall, the mean (95% CI) AUC0-4 during pregnancy for all seven subjects was 80% (51.3, 107.8) of the postpartum value (P = 0.053, two-tailed t-test; P = 0.027, one-tailed t-test). CONCLUSION: These results are consistent with our hypothesis that the clearance of metformin increases in pregnancy as a result of enhanced renal elimination. A larger study is required to establish whether metformin dose adjustments are required in late pregnancy to maintain therapeutic effect.

Adult↗

PubMed2006

Family average income and diagnosed Type 2 diabetes in urban and rural residents in regional mainland China.

AIMS: To explore the relationship between family average income (FAI; an index of socio-economic status) and Type 2 diabetes in a region of mainland China. METHODS: Population-based cross-sectional study, conducted between October 2000 and March 2001 in administrative villages (n = 45) randomly selected from three urban districts and two rural counties of NanJing municipality, mainland China, with a regional population of 5.6 million. Participants were all local residents aged > or = 35 years old (n = 29 340); 67.7% from urban areas, 32.3% from rural areas, 49.8% male and 50.2% female. RESULTS: The response rate of eligible participants was 90.1%. The overall prevalence of self-reported Type 2 diabetes was 1.9%. After adjustment for possible confounding variables (age, gender, area of residence, body mass index, educational level, smoking status, occupational and leisure-time physical activity), participants in the higher and middle FAI categories were more than twice as likely to have Type 2 diabetes as those in the lower FAI category. CONCLUSIONS: The prevalence of Type 2 diabetes is positively related to socio-economic status (indexed by FAI) in Chinese at the population level. After controlling for potential confounding factors, people in higher socio-economic status groups are more likely to have Type 2 diabetes. These associations are consistent with other effects of epidemiological transition and identify a need for preventive initiatives.

Adult↗

PubMed2006

Ultrasound biomicroscopy of Chinese eyes with iridocorneal endothelial syndrome.

AIM: To document the ultrasound biomicroscopic (UBM) findings in Chinese patients with iridocorneal endothelial (ICE) syndrome. METHODS: 21 patients with ICE syndrome and 15 normal subjects underwent UBM. UBM findings of anterior segment were compared between normal subjects and three clinical types of ICE syndrome: progressive iris atrophy (PIA), Chandler's syndrome (CS), and Cogan-Reese syndrome (CRS). RESULTS: Central anterior chamber depth was significantly less in patients with ICE syndrome (2.25 (SD 0.32) mm) than in normal subjects (2.76 (0.32) mm). Peripheral anterior synechiae were observed in all the ICE patients by UBM. Three out of four CRS subjects showed an "arborised" shape of iridocorneal angle. Two eyes out of 10 with CS presented bridge-shaped synechiae. A membrane-like mound was observed in iridocorneal angle in two patients: one with CRS and one with CS. UBM was found to be more effective in detecting peripheral anterior synechiae (PAS) and iris atrophy than slit lamp microscopy and gonioscopy, mainly because of corneal oedema in patients with CS. Four out of 11 patients with unilateral ICE syndrome had shallow or closed anterior chamber angles in their fellow eyes. Two of them successfully responded to laser peripheral iridotomy. CONCLUSIONS: UBM is an effective method to reveal the anterior segment features and provides a useful tool in the diagnosis of ICE syndrome. Different subtypes of ICE syndrome may have different UBM manifestations. UBM can help to identify angle closure in the fellow eye of unilateral ICE syndromes.

Adult↗

PubMed2006

A family-based association study of megsin A23167G polymorphism with susceptibility and progression of IgA nephropathy in a Chinese population.

AIMS: To investigate the association of megsin A23167G polymorphism with susceptibility and progression of IgA nephropathy in Chinese population. METHODS: 435 IgA nephropathy patients and their family members were recruited for a family-based association study. Genotypes of megsin A23167G were determined by direct sequencing. The results were analyzed by transmission disequilibrium test (TDT) and haplotype relative risk (HRR). Clinical data and histological scores of renal lesions were compared between patients with different genotypes. According to disease stability, IgA nephropathy patients were divided into progressive group and stable group. The distribution of genotype frequencies were compared between the 2 groups. RESULTS: TDT revealed that megsin 23167G alleles were transmitted more frequently from heterozygous parents to patients than expected (classical TDT: chi2 = 5.435, p = 0.020, extended TDT: chi2 = 5.017, p = 0.025). HRR analyses showed significant differences between transmitted and nontransmitted allele frequencies (chi2 = 7.006, p = 0.008, HRR = 1.762). The scores of glomerular index and glomerular sclerosis index were higher in GG genotype patients than those in other genotypes (F = 4.570, p = 0.033, F = 4.324, p = 0.038, respectively). The distribution frequency of GG genotype in the progressive group was higher than that of the stable group (chi2 = 4.370, p = 0.037). No statistical difference was found in tubulo-interstitial index, vascular index and clinical characteristics between the 2 groups. CONCLUSION: The polymorphism of megsin A23167G is associated with susceptibility and progression of IgA nephropathy in Chinese population. GG genotype is associated with severe histological lesions and progression of the disease.

Adult↗

PubMed2006

Imaging and nanomedicine for diagnosis and therapy in the central nervous system: report of the eleventh annual Blood-Brain Barrier Disruption Consortium meeting.

The blood-brain barrier (BBB) presents a major obstacle to the treatment of malignant brain tumors and other central nervous system (CNS) diseases. The Eleventh Annual Blood-Brain Barrier Disruption Consortium Meeting was convened to discuss recent advances and future directions in imaging and nanomedicine. Two sessions, one on Cell and Molecular Imaging in the CNS and another on Nanotechnology, Nanobiology, and Nanomedicine, were held March 17-18, 2005, in Portland, Ore. CNS imaging presentations targeted differentiating tumor, neural lesions, and necrosis from healthy brain tissue; methods of delivery of imaging agents across the BBB; and new iron oxide-based nanoparticle contrast agents for MR imaging. Nanobiology presentations covered the development of new nanotechnology and its use in imaging, diagnosis, and therapy in the CNS. Discussions at this meeting stressed the role of biotechnology in the convergence of CNS imaging and nanomedicine and are summarized in this article.

Blood-Brain Barrier↗

PubMed2006

Transcriptional and post-transcriptional controls of survivin in cancer cells: novel approaches for cancer treatment.

Survivin is a novel member of the inhibitor of apoptosis (IAP) protein family, and its aberrant expression in cancer cells has been shown to be associated with tumorigenesis, cancer progression, radiation/drug resistance and shorter patient survival. Survivin is also expressed in certain human adult tissues and cells, and has been shown to play a role in physiology. Interestingly, targeting survivin for cancer treatment did not show obvious toxicity to normal tissues and cells. This suggests that the mechanism for the regulation and function of survivin may actually be different in cancer cells as compared to normal cells. This review intends to summarize the most important information about the transcriptional and/or post-transcriptional controls of survivin in cancer cells. Further studies along this line may find essential interfaces for the development of novel approaches for cancer therapeutics.

Biomarkers, Tumor↗

PubMed2005

Internal fiducial markers can assist dose escalation in treatment of prostate cancer: result of organ motion simulations.

Use of internal fiducial markers and electronic portal imaging (EPI) to realign patients has been shown to significantly reduce positioning uncertainties in prostate radiation treatment. This creates the possibility of improving the treatment by decreasing the planning target volume (PTV) margin added to the clinical target volume (CTV), which in turn may allow dose escalation. Conformal treatment plans for three prostate cancer patients were evaluated by using different PTV margins with dose prescription of 70 Gy/35 fr initially. Two beam arrangements, 4-field-box (4FB) and 4-field-oblique (4FO), were used. Then, two dose escalation schemes, 74 Gy and 78 Gy, with tighter PTV margins, were chosen from the first simulation and were tested. A Monte Carlo model was developed to simulate the daily geometric uncertainty and calculate the dose to each organ. After the whole treatment, dose-volume histograms were produced and tumour control probability, prostate equivalent uniform dose and the effective dose to critical organs were calculated. By comparing these radiobiological metrics, optimized dose escalation schemes were found. The results show that using internal fiducial markers and EPI, the prescription dose can be escalated to 78 Gy/39 fr with a 4 mm PTV margin. Based on the available dose-response data for intermediate risk prostate patients, this is estimated to result in a 20% increase of local control and significantly reduced rectal complications.

Algorithms↗

PubMed2005

Tear function and goblet cell density after pterygium excision.

PURPOSE: To evaluate the short-term effect of pterygium excision on tear function and conjunctival goblet cell density. METHODS: In all, 70 patients (70 eyes) with primary pterygia who underwent a bare-sclera procedure were enrolled in this study. Tear break-up time, Schirmer, and tear-ferning tests and conjunctival goblet cell density obtained by impression cytology were evaluated before and 1 month after surgery. RESULTS: At 1 month postoperation, the tear break-up time (11.49+/-3.76 s) was significantly prolonged when compared with the preoperation tear break-up time (9.74+/-3.43 s, P=0.002). Before surgery, only 17% of the patients showed normal crystallization in the tear-ferning test. This proportion was significantly increased to 90% 1 month after surgery (P<0.001). There is no significant difference in the Schirmer test value between pre- and postsurgery (P>0.05). The mean goblet cell density in conjunctival impression specimens before surgery was 41.82+/-18.29/10 fields, which was increased significantly 1 month after surgery (P<0.001) with a mean cell density of 50.67+/-18.71/10 fields. CONCLUSION: Tear function in patients with primary pterygium improves after pterygium excision, which indicates that pterygium has a close relationship with dry eye.

Adult↗

PubMed2005

Effects of mechanical pressure on intracellular calcium release channel and cytoskeletal structure in rabbit mandibular condylar chondrocytes.

Many signal molecules are involved in mechanotransduction process, among which intracellular calcium and cytoskeleton are two of the most important ones. This study investigated the changes of intracellular calcium and cytoskeleton under pressure and the effects of intracellular calcium variation on cytoskeleton responses to the pressure in rabbit mandibular condylar chondrocytes (MCCs). In vitro cultured MCCs from 2-week-old New Zealand rabbits were incubated for observation of intracellular calcium variation under laser scanning microscope. Coomassie BB staining was used to observe the characteristics of cytoskeleton. We found that intracellular calcium increased following the irritation by 1,25(OH)2D3, whereas it remained unchanged when inositol triphosphate receptor (IP3R) channel was blocked by heparin. Pretreatment with pressure of 90 kPa for 60 min enhanced the sensitivity of IP3R channel and caused higher intracellular calcium concentration. The cytoskeletons of MCCs were revealed correspondingly uniform and reticular in the control, most of which showed higher expression in tighter arrangement under continuous pressure of 90 kPa for 60 min but lower expression when the pressure time was prolonged to 360 min. When MCCs were pretreated with heparin, the cytoskeleton of them displayed sparsely and discontinuously under 90 kPa for 60 min. To sum up, both cytoskeleton and intracellular calcium participate in the transition process of mechanical signal to biological effects of MCC. However, the decrease of intracellular calcium resulted from IP3R channel blocking obviously interferes the recomposition of cytoskeleton under mechanical pressure, which suggests that calcium message is indispensable to the cytoskeleton response of MCC under pressure.

Animals↗

PubMed2005

Isolating single-wall carbon nanohorns as small aggregates through a dispersion method.

An approach to isolating small aggregates of single-wall carbon nanohorns (SWNHs) is presented. SWNHs are ultrasonically treated in an aqueous solution of surfactant, resulting in dispersion of SWNH aggregates. Subsequent centrifuging enables the separation of small aggregates from larger aggregates or agglomerations and removal of graphitic particles (GG balls), the main impurity. The SWNHs obtained in this way were purified and formed small aggregates, thus exhibiting characteristics superior to those of SWNHs before treatment. We believe that the ability to isolate small SWNH aggregates in an aqueous solution should contribute to their application in the fields of biological sensing and drug delivery systems.

Journal Article↗

PubMed2005

Leisure activity and risk of cognitive impairment: the Chongqing aging study.

The authors followed 5,437 people aged 55 years and older with normal baseline Mini-Mental State Examination score annually for 5 years. The mean incidence of cognitive impairment was 2.3% per year. Cognitive activities in both the individual item (playing board games and reading) and the composite measure were associated with the reduced risk of cognitive impairment, while watching television was associated with an increased risk of cognitive impairment.

Aged↗

PubMed2005

Lateral branches of dorsal sacral nerve plexus and the long posterior sacroiliac ligament.

Non-specific low back pain and peripartum pelvic pain have aetiologies that may feature the sacroiliac region. This region possesses many potential pain-generating structures sharing common sensory innervation which makes clinical differentiation of pathoanatomy difficult. This anatomical study explores the relationship between the long posterior sacroiliac ligament (LPSL) and the lateral branches of the dorsal sacral nerve plexus. Twenty-five sides of the pelvis from 16 cadavers were studied, three for histological analysis and 22 for gross anatomical dissection. We found that the LPSL is penetrated by the lateral branches of the dorsal sacral rami of predominantly S2 (96%, 21/22) and S3 (100%, 22/22), variably of S4 (59%, 13/22) and rarely of S1 (4%, 1/22). Some of the penetrating lateral branches give off nerve fibres that disappear within the ligament. These findings provide an anatomical basis for the notion that the LPSL is a potential pain generator in the posterior sacroiliac region.

Aged↗

PubMed2005

Chinese herbal medicine for schizophrenia.

BACKGROUND: Traditional Chinese medicine (TCM) was the main form of treatment in China for psychiatric illnesses until the development of antipsychotic drugs in the 1950's. Antipsychotic drugs have become the primary intervention for schizophrenia, although herbal medicines can still form part of the treatment. OBJECTIVES: To review Chinese herbal medicine, used alone or as part of a TCM approach, for people with schizophrenia and related psychoses. SEARCH STRATEGY: We undertook electronic searches of the Cochrane Schizophrenia Group's register (December 2003), the Traditional Chinese Medical Literature Analysis and Retrieval Database (TCMLARS) (October 2003), Chinese Biomedical Database (CBM) (December 2003), China National Knowledge Infrastructure Database (May 2004), Complementary Medicine Database (AMED) (December 2003). We contacted the Chinese Cochrane Centre, the Cochrane Complementary Medicine Field and first authors of included studies and inspected reference lists for additional studies. SELECTION CRITERIA: We included all relevant randomised controlled trials involving people with schizophrenia-like illnesses, allocated to Chinese herbal medicine, including any Chinese herbs (single or mixture), compared with placebo/no treatment or antipsychotic drugs. DATA COLLECTION AND ANALYSIS: We independently extracted data and calculated fixed effects relative risk (RR), the 95% confidence intervals (CI) for homogeneous dichotomous data, and, where appropriate, the number needed to treat (NNT) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD). MAIN RESULTS: Only one small trial of the seven included studies truly evaluated TCM for schizophrenia. The other trials evaluated Chinese herbs for schizophrenia. We found one study comparing Chinese herbal medicine with antipsychotic drugs. Data for the global state outcome 'no change/worse' favoured people allocated to antipsychotic medication (n=90, RR 1.88 CI 1.2 to 2.9, NNH 4 CI 2 to 12). Six trials compared Chinese herbal medicine in combination with antipsychotic with antipsychotic drugs alone. One trial found global state 'not improved/worse' favoured the herbal medicine/antipsychotic combination (n=123, RR 0.19 CI 0.1 to 0.6, NNT 6 CI 5 to 11). Two studies (n=103) also found short-term data from the Clinical Global Impression scale favoured the herbal medicine plus antipsychotic group (WMD -0.46 CI -0.9 to -0.1) compared with those given only antipsychotics. Significantly fewer people in the experimental group left the study early compared with those given antipsychotics alone (n=1004, 6 RCTs, RR 0.30 CI 0.16 to 0.58, NNT 21 CI 18 to 35). Reports of constipation were significantly lower in the treatment group compared to those receiving antipsychotics (n=67, 1 RCT, RR 0.03 CI 0.0 to 0.5, NNH 2 CI 2 to 4). AUTHORS' CONCLUSIONS: Chinese herbal medicines, given in a Western biomedical context, may be beneficial for people with schizophrenia when combined with antipsychotics. Traditional Chinese medicine is also under-evaluated, but results from one pioneering study that attempted to evaluate TCM should encourage further trials.

Antipsychotic Agents↗

PubMed2005

Adenovirus expressing an NPC1-GFP fusion gene corrects neuronal and nonneuronal defects associated with Niemann pick type C disease.

Niemann Pick type C (NPC) disease is an autosomal recessive disorder characterized by abnormal cholesterol metabolism and accumulation in lysosomal and endosomal compartments. Although peripheral organs are affected, the progressive neurodegeneration in the brain is typically most deleterious, leading to dystonia, ataxia, seizures, and premature death. Although the two genes underlying this disorder in humans and mouse models of the disease have been identified (NPC1 in 95% and NPC2/HE1 in 5% of human cases), their cellular roles have not Been fully defined, and there is currently no effective treatment for this disorder. To help address these issues, we constructed a recombinant adenovirus, Ad(NPC1-GFP), which contains a cDNA encoding a mouse NPC1 protein with a green fluorescent protein (GFP) fused to its C-terminus. Fluorescence microscopy and cholesterol trafficking assays demonstrate that the GFP-tagged NPC1 protein is functional and detectable in cells from different species (hamster, mouse, human) and of different types (ovary-derived cells, fibroblasts, astrocytes, neurons from peripheral and central nervous systems) in vitro. Combined with results from time-lapse microscopy and in vivo brain injections, our findings suggest that this adenovirus offers advantages for expressing NPC1 and analyzing its cellular localization, movement, functional properties, and beneficial effects in vitro and in vivo.

Adenoviridae↗