Audiological and genetic features of the mtDNA mutations

CONCLUSIONS

Significant difference in the incidence of mitochondrial DNA (mtDNA) mutations was found between the Chinese and USA populations. The identification of the mtDNA A1555G mutation in a large proportion of Chinese probands with nonsyndromic sensorineural hearing loss (NSHL) provides a molecular explanation for the high prevalence of aminoglycoside-induced deafness in China.

OBJECTIVE

The aim was to characterize the audiological and genetic features of NSHL due to mutations in mtDNA.

SUBJECTS AND METHODS

The mtDNA and audiogram analyses were performed in 498 NSHL patients (290 from China and 208 from the USA) with and without history of aminoglycoside exposure. A PCR and restriction enzyme digestion protocol was used for mutational screening and the European Workshop on Genetic Hearing Loss criteria were applied for audiological classification.

RESULTS

All Chinese probands (15.5%) with mtDNA mutation were found to carry the homoplasmic mtDNA A1555G mutation, whereas four probands (1.9%) from the USA were found to carry the mtDNA A1555G and two (1%) had mtDNA G7444A. Approximately 63% of the probands with mtDNA mutations had post-lingual hearing loss and 56.8% of them had a medical history of exposure to aminoglycosides. Hearing losses are bilateral, sensorineural, and symmetric. The main audiogram shapes found were sloping.

Metal contamination in the sediment, pondweed, and snails of a stream receiving effluent from a lead/zinc mine in southern China

This study assessed the potential of Potamogeton crispus and Pomacea canaliculata as biomonitors of sedimentary metal contamination. The results indicate P. crispus possesses several attributes of a biomonitor and its tissue concentrations of Cd, Pb and Zn may reflect the levels of sedimentary contamination by these metals. Although P. canaliculata can accumulate metals to high levels and serve as an indicator of metal contamination, its tissue metal concentrations did not correlate with those of the sediments or macrophytes.

Using SELDI-TOF MS to identify serum biomarkers of rheumatoid arthritis

OBJECTIVES

No satisfactory biomarkers are currently available to screen for rheumatoid arthritis (RA). We have developed and evaluated surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) for detection and analysis of multiple proteins for distinguishing individuals with RA from control individuals.

METHODS

A total of 156 serum samples from 90 RA patients, 30 patients with ankylosing spondylitis (AS), and 36 healthy individuals were examined by SELDI technology. Spectral data were analysed by the support vector machine (SVM) approach and potential biomarkers were chosen for system training and were used to construct a diagnostic model.

RESULTS

Pattern 1, consisting of four protein peaks with m/z values of 3899, 4594, 7566, and 13,842, distinguished RA from the healthy samples with sensitivity of 90.0% and a specificity of 91.7%. Pattern 2, consisting of m/z peaks 4287 and 6471, distinguished RA from AS with a sensitivity of 86.7% and a specificity of 85.0%.

CONCLUSION

The combination of SELDI-TOF MS and SVM could facilitate the discovery of better biomarkers for RA and also provide a useful tool for molecular diagnosis in the future.

A preliminary microsatellite genetic map of the ostrich (Struthio camelus)

Molecular genetic maps can provide information for the identification and localization of major genes associated with quantitative traits. However, there are currently no published genetic linkage maps for any ratites. Herein, a preliminary genetic map of ostrich was developed using a two-generation ostrich reference family by linkage analysis of 104 polymorphic microsatellite markers, including 40 novel markers reported in this study. A total of 35 microsatellite markers were placed into 13 linkage groups. Five linkage groups are composed of three or more loci, whereas the remaining eight groups each contained two markers. The sex-averaged map spans 365.4 cM. The marker interval of each linkage group ranges from 5.3 to 25.4 cM, and the average interval distance is 16.61 cM. The male map covers 342.7 cM, with an average intermarker distance of 15.58 cM, whereas the female map is 456.7 cM, with the average intermarker spacing of 20.76 cM. In order to screen the orthologous loci between ostrich and chicken, all of the flanking sequences of the 104 polymorphic loci, nine monomorphic loci and a further 12 reported microsatellite loci for ostrich were screened against the chicken genomic sequence using the BLAST algorithm (Altschul et al., 1990), and corresponding orthologs were found for 13 sequences. The microsatellite loci and genetic map developed in this study will be useful for QTL mapping, population genetics and phylogenetic studies in the ratite. In addition, the 13 orthologous loci identified in this study will be advantageous to the construction of a comparative genetic map between chicken and ostrich.

Circadian modulation of light-induced locomotion responses in Drosophila melanogaster

The relationship between light and the circadian system has long been a matter of discussion. Many studies have focused on entrainment of light with the internal biological clock. Light also functions as an environmental stimulus that affects the physiology and behaviour of animals directly. In this study, we used light as an unexpected stimulus for flies at different circadian times. We found that wildtype flies showed circadian changes in light-induced locomotion responses. Elevation of locomotor activity by light occurred during the subjective night, and performance in response to light pulses declined to trough during the subjective day. Moreover, arrhythmic mutants lost the rhythm of locomotion responses to light, with promotion of activity by light in timeless(01)mutants and inhibition of activity by light in Clock(ar)mutants. However, neither ablation of central oscillators nor disturbance of the functional clock inside compound eyes was sufficient to disrupt the rhythm of light responses. We show that, compound eyes, which have been identified as the control point for normal masking (promotion of activity by light), are sufficient but not necessary for paradoxical masking (suppression of activity by light) under high light intensity. This, taken together with the clear difference of light responses in wildtype flies, suggests that two different masking mechanisms may underlie the circadian modulation of light-induced locomotion responses.

Magnetic nanoparticles with core/shell structures

Magnetic nanoparticles with core/shell structures are an important class of functional materials, possessing unique magnetic properties due to their tailored dimensions and compositions. This paper reviews mainly our recent advances in the preparation and characterizations of core/shell structured magnetic materials, focusing in nonmagnetic, antiferromagnetic, or ferro/ferri-magnetic shell coated magnetic core particles. And some of the unique properties of core-shell materials and their self-assembly are presented. Shell layers are shown to serve various functions. A broad demonstration of the successful blend of these types of materials synthesis, microstructural evolution and control, new physics and novel applications that is central to research in this field is presented.

Genomewide association for schizophrenia in the CATIE study: results of stage 1

Little is known for certain about the genetics of schizophrenia. The advent of genomewide association has been widely anticipated as a promising means to identify reproducible DNA sequence variation associated with this important and debilitating disorder. A total of 738 cases with DSM-IV schizophrenia (all participants in the CATIE study) and 733 group-matched controls were genotyped for 492,900 single-nucleotide polymorphisms (SNPs) using the Affymetrix 500K two-chip genotyping platform plus a custom 164K fill-in chip. Following multiple quality control steps for both subjects and SNPs, logistic regression analyses were used to assess the evidence for association of all SNPs with schizophrenia. We identified a number of promising SNPs for follow-up studies, although no SNP or multimarker combination of SNPs achieved genomewide statistical significance. Although a few signals coincided with genomic regions previously implicated in schizophrenia, chance could not be excluded. These data do not provide evidence for the involvement of any genomic region with schizophrenia detectable with moderate sample size. However, a planned genomewide association study for response phenotypes and inclusion of individual phenotype and genotype data from this study in meta-analyses hold promise for eventual identification of susceptibility and protective variants.

C5 blockade with conventional immunosuppression induces long-term graft survival in presensitized recipients

We explored whether a functionally blocking anti-C5 monoclonal antibody (mAb) combined with T- and B-cell immunosuppression can successfully prevent antibody-mediated (AMR) and cell-mediated rejection (CMR) in presensitized murine recipients of life-supporting kidney allografts. To mimic the urgent clinical features of AMR experienced by presensitized patients, we designed a murine model in which BALB/c recipients were presensitized with fully MHC-mismatched C3H donor skin grafts one week prior to C3H kidney transplantation. Presensitized recipients demonstrated high levels of circulating and intragraft antidonor antibodies and terminal complement activity, rejecting grafts within 8.5 +/- 1.3 days. Graft rejection was predominantly by AMR, characterized by interstitial hemorrhage, edema and glomerular/tubular necrosis, but also demonstrated moderate cellular infiltration, suggesting CMR involvement. Subtherapeutic treatment with cyclosporine (CsA) and LF15-0195 (LF) did not significantly delay rejection. Significantly, however, the addition of anti-C5 mAb to this CsA/LF regimen prevented terminal complement activity and inhibited both AMR and CMR, enabling indefinite (>100 days) kidney graft survival despite the persistence of antidonor antibodies. Long-term surviving kidney grafts expressed the protective proteins Bcl-x(S/L) and A-20 and demonstrated normal histology, suggestive of graft accommodation or tolerance. Thus, C5 blockade combined with routine immunosuppression offers a promising approach to prevent graft loss in presensitized patients.

Etoposide sensitivity does not predict MLL rearrangements or risk of therapy-related acute myeloid leukemia

Therapy-related acute myeloid leukemia (t-AML) caused by MLL rearrangements (rMLL) can arise from topoisomerase II agents. However, whether rMLL-related leukemogenesis is inextricably linked to drug cytotoxicity remains controversial. We therefore compared (i) rMLL in children with acute lymphoblastic leukemia (ALL) who developed t-AML and those who did not, (ii) epipodophyllotoxin toxicity in patients with t-AML and in controls, and (iii) rMLL in cells sensitive to etoposide and in those resistant to etoposide. In children with ALL, rMLL appeared to be more frequent in children who developed t-AML than in those who did not (seven pairs, P = 0.04), although independent of the cumulative etoposide dose (P = 0.5). Similarly, the frequency of epipodophyllotoxin-related toxicities did not differ between patients with t-AML and controls (26 pairs, P > 0.17). Moreover, in 25 cell lines, etoposide-induced MLL fusions did not differ in sensitive vs. resistant lines at equitoxic concentrations (P = 0.65). Together, these results indicate that epipodophyllotoxin-mediated leukemogenesis is not directly linked to drug cytotoxicity.

Role of NBCe1 and AE2 in secretory ameloblasts

The H(+)/base transport processes that control the pH of the microenvironment adjacent to ameloblasts are not currently well-understood. Mice null for the AE2 anion exchanger have abnormal enamel. In addition, persons with mutations in the electrogenic sodium bicarbonate co-transporter NBCe1 and mice lacking NBCe1 have enamel abnormalities. These observations suggest that AE2 and NBCe1 play important roles in amelogenesis. In the present study, we aimed to understand the roles of AE2 and NBCe1 in ameloblasts. Analysis of the data showed that NBCe1 is expressed at the basolateral membrane of secretory ameloblasts, whereas AE2 is expressed at the apical membrane. Transcripts for AE2a and NBCe1-B were detected in RNA isolated from cultured ameloblast-like LS8 cells. Our data are the first evidence that AE2 and NBCe1 are expressed in ameloblasts in vivo in a polarized fashion, thereby providing a mechanism for ameloblast transcellular bicarbonate secretion in the process of enamel formation and maturation.

Effect of intensity clamping on laser ablation by intense femtosecond laser pulses

We have experimentally demonstrated that because of intensity clamping, when the laser peak power is higher than the critical power for self-focusing, further increase of the laser power cannot result in corresponding increase of the laser ablation rate of a metallic sample placed in gases. The ablation rate will finally approach a stabilized value. Also, the experimental technique implemented in our work could be potentially used to measure the self-focusing critical power and the nonlinear refractive index.

Effect of supervised exercise intervention on metabolic risk factors and physical fitness in Chinese obese children in early puberty

The aim of this paper was to study the effect of long-term supervised exercise-induced weight maintenance on metabolic risk factors and physical fitness in obese children in early puberty. A total of 49 obese children aged 12-14 years were divided into control and exercise groups. The children in the exercise group accepted exercise intervention supervised by a professional sports teacher for 9 of the 12 months. All participants in both groups received health education once every 3 months. Anthropometry and fasting serum lipids, glucose, insulin and homeostatic model assessment for insulin resistance (HOMA-IR) were measured at months 0, 3, 9, 12 of the intervention. Physical fitness was determined before and after intervention. After the intervention (i) BMI was reduced by 0.6 (P < 0.05) in the exercise group, but increased by 0.5 (P < 0.05) in the control group, compared with the pre-intervention level at the end of 9-month intervention; (ii) Triglyceride levels in the exercise group significantly decreased by 23.1% by 3 months (P < 0.05), and by 30.2% after 9 months (P < 0.05), but increased by 50% (P < 0.05) in the control group; high density lipoprotein-cholesterol (HDL-C) decreased more by 35% (P < 0.05) in the controls than in the exercise group (P < 0.05); (iii) Fasting serum glucose, insulin level and HOMA-IR decreased, respectively, by 23.1%, 36.6% and 48.5% in the exercise group at 9 months (P < 0.05), whereas glucose levels increased by 10.9% (P < 0.05) in the control group; (iv) Exercise performance, such as upper- and lower-limb strength, flexibility and endurance, were enhanced by 17.9%, 12.3%, 22.3% and 20.4% (P < 0.01), respectively and (v) At 12 months, i.e. 3 months after terminating the supervised exercise, serum triglycerides, glucose, insulin and HOMA-IR level all returned to the pre-intervention level. Supervised decrement exercise can effectively slow the progress of obesity, improve insulin sensitivity and metabolic risk factors, but once the supervised exercise is stopped, the health benefits weaken or vanish. The key to helping these obese children is for them to cultivate good exercise habits which are sustained throughout their lives.