Defect solitons in two-dimensional optical lattices

We report on the existence and stability of solitons in a defect embedded in a square optical lattice based on a photorefractive crystal with focusing saturable nonlinearity. These solitons exist in different bandgaps due to the change of defect intensity. For a positive defect, the solitons only exist in the semi-infinite gap and can be stable in the low power region but not the high power region. For a negative defect, the solitons can exist not only in the semi-infinite gap, but also in the first gap. With increasing the defect depth, these solitons are stable within a moderate power region in the first gap while unstable in the entire semi-infinite gap.

Presbyopia and cataract: a question of heat and time

Not only are human lenses different in many ways from those of non-primates, they also undergo dramatic changes with age. These age-dependent alterations lead to perturbations in the properties of older lenses, and ultimately to disturbances in visual function, which typically become apparent at middle age. Recent data suggest that many, if not all, of these age-dependent features can be traced to the lack of macromolecular turnover in the lens and to the inexorable modifications to proteins and membrane components over a period of decades. Exposure of lenses to heat can reproduce many of these alterations, suggesting that long-term incubation at body temperature may be an important factor in aging the human lens. Two conclusions flow from this. Firstly, the human lens may be an ideal tissue for studying macromolecular aging in man. Secondly, it will be extremely challenging to examine the origin of human age-related conditions, such as presbyopia and nuclear cataract, using traditional laboratory animals. Characterising the unfolding and decomposition of long-lived macromolecules appears to provide the key to understanding the two most common human lens disorders: presbyopia and age-related nuclear cataract.

α- and β-crystallins modulate the head group order of human lens membranes during aging

PURPOSE

To examine the physical properties of human lens cell membranes as a function of age.

METHODS

The environment of the phospholipid head groups in fiber cell membranes from human lenses, aged 22 to 83 years, was assessed with Laurdan and two-photon confocal microscopy. The effect of mild thermal stress on head group order was studied with lens pairs in which one intact lens was incubated at 50 °C. Dihydrosphingomyelin vesicles were preloaded with Laurdan, α-, β-, or γ-crystallin was added, and surface fluidity was determined.

RESULTS

The membrane head group environment became more fluid with age as indicated by increased water penetration. Furthermore, these changes could be replicated simply by exposing intact human lenses to mild thermal stress; conditions which decreased the concentration of soluble α- and β-crystallins. Vesicle binding experiments showed that α- and β-, but not γ-, crystallins markedly affected head group order.

CONCLUSIONS

The physical properties of cell membranes in the lens nucleus change substantially with age, and α- and β-crystallins may modulate this effect. β-Crystallins may therefore play a role in lens cells, and cells of other tissues, apart from being simple structural proteins. Age-dependent loss of these crystallins may affect membrane integrity and contribute to the dysfunction of lenses in older people.

Increased risk of high-grade hypertension with bevacizumab in cancer patients: a meta-analysis

BACKGROUND

Hypertension is associated with the use of bevacizumab, an angiogenesis inhibitor widely used in cancer therapy. Currently, the risk of severe hypertension associated with bevacizumab is unclear. We performed a systematic review and meta-analysis of published randomized-controlled clinical trials (RCTs) to assess the risk of high-grade hypertension in cancer patients treated with bevacizumab.

METHODS

Databases from PUBMED, the Web of Science, and abstracts presented at the American Society of Clinical Oncology conferences until May 2009 were searched to identify relevant studies. Eligible studies included prospective RCTs in which bevacizumab was directly compared with controls in cancer patients receiving concurrent antineoplastic therapy. Summary incidence, relative risk (RR), and 95% confidence interval (CI) were calculated employing a fixed- or random-effects model based upon the heterogeneity of the included studies.

RESULTS

A total of 12,656 patients with a variety of tumors from 20 studies were included for the analysis. The incidence of all-grade hypertension in patients receiving bevacizumab was 23.6% (95% CI: 20.5-27.1) with 7.9% (95% CI: 6.1-10.2) being high-grade (grade 3 or 4). Patients treated with bevacizumab had a significantly increased risk of developing high-grade hypertension with an RR of 5.28 (95% CI: 4.15-6.71, P < 0.001) in comparison with controls. Even though not statistically significant, there was a trend suggesting that bevacizumab may increase the risk of hypertensive crisis (grade 4) with an RR of 3.16 (95% CI: 0.91-10.90). The increased risk of high-grade hypertension was observed in patients receiving bevacizumab at 2.5 mg/kg/week (RR = 4.78, 95% CI: 3.59-6.36) as well as 5 mg/kg/week (RR = 5.39, 95% CI: 3.68-7.90). The risk of high-grade hypertension may vary with tumor types, with RRs ranging from 2.49 (95% CI: 0.94-6.59) in patients with mesothelioma to 14.80 (95% CI: 0.92-238.51) in patients with breast cancer.

CONCLUSION

Bevacizumab may significantly increase the risk of high-grade hypertension in cancer patients. Close monitoring and adequate management are highly recommended to decrease cardiovascular complications.

Nutrition support with glutamine dipeptide in patients undergoing liver transplantation

AIM

The effect of total parenteral nutrition (TPN) support supplemented with alanyl-glutamine (Ala-Gln) dipeptide was investigated in a randomized, controlled clinical trial.

METHODS

Sixty-five patients with the diagnosis of end-stage liver disease or hepatic cellular carcinoma admitted for orthotopic liver transplantation were randomly divided into 3 groups: diet group (n = 21), TPN group (n = 22), and Gln group (n = 22). Patients in the TPN and Gln groups received isocaloric and isonitrogenous TPN for 7 days. Venous heparin blood samples were obtained for assay on days 2 and 9 after surgery; we performed routine pathologic tests.

RESULTS

Compared with the results on day 9 in the TPN group, there was a significant increase in the prognostic nutrition index and in prealbumin among the Gln group. Aspartate aminotransferase improved significantly by Gln treatment compared with traditional TPN support (P < .05). The pathologic results also showed Gln supplementation to reduce hepatic cell injury. A significant decrease in postoperative hospital stay was observed in the Gln group.

CONCLUSIONS

Posttransplant TPN support greatly improved protein metabolism and nutritional state of patients. TPN with Ala-Gln helped to improve synthetic function and to reduce the injury to a transplanted liver.

Embryonic-like stem cell derived from adult bone marrow: immature morphology, cell surface markers, ultramicrostructure and differentiation into multinucleated fibers in vitro

Embryonic-like stem cell (ELSC), expressing part of surface markers of human embryonic stem cells, may be a better candidate for cell therapy of degenerative muscular disease than mesenchymal stem cell (MSC). We isolated ELSC and MSC from bone marrow, respectively, and compared their differences in the characteristics and the capacity of myogenic differentiation. Results showed that ELSC could be isolated successfully from 3 adult bone marrow samples by using serum-free medium with 10ng/ml basic fibroblast growth factor (bFGF). At the same cell density, MSC could also be isolated from the same samples by using DMEM/F12 medium containing 10% new cattle serum. However, ELSC appeared as small, morphologically slenderer, upregulated expression of SSEA-4 and ultramicroscopically more immature than MSC derived from the same samples. Immunofluorescent staining and RT-PCR analysis showed ELSC weakly expressed Oct-4, Nanog-3 and Sox-2. Moreover, ELSC and MSC could be induced into long, multinucleated fibers expressing myogenin and myosin heavy chain (MHC) in myogenic differentiation medium, but by day 10, proportion of multinucleated fibers positive for MHC was respectively 25.0%+/-6.9% and 13.8%+/-7.6% in ELSC and MSC culture. These data suggest that bone marrow derived ELSC represent an ideal candidate for cell therapy of degenerative muscular disease.

Coherent beam transformations using multimode waveguides

Physical insights and characteristics of beam transformations based on multimode interference (MMI) in multimode waveguides are illuminated and analyzed. Our calculations show that, utilizing a short piece of cylindrical multimode waveguide, an input Gaussian beam can be readily transformed to frequently desired beams including top-hat, donut-shaped, taper-shaped, and Bessel-like beams in the Fresnel or the Fraunhofer diffraction range, or even in both ranges. This is a consequence of diffractive propagation of the field exiting the waveguide. The performance of the beam shaper based on MMI can be controlled via tailoring the dimensions of the multimode waveguide or changing the signal wavelength. This beam shaping technique is investigated experimentally using monolithic fiber devices consisting of a short piece of multimode fiber (approximately 10 mm long) and a single-mode signal delivery fiber.

An evaluation of the diabetic kidney disease definition in chinese patients diagnosed with type 2 diabetes mellitus

The concomitant presence of retinopathy may be helpful in discriminating kidney pathology in type 2 diabetes. This cross-sectional study evaluated the ability to predict the likelihood of patients having diabetic kidney disease (DKD) by comparing the percentage incidence of diabetic retinopathy in different subgroups of Chinese patients with type 2 diabetes (n = 668). The prevalence of chronic kidney disease in the patients was 63.3% (6.6% with DKD, 41.0% with possible DKD and 15.7% with non-diabetic renal disease [NDRD]). The percentage of patients with diabetic retinopathy in the DKD group (63.6%) was significantly higher than in the possible DKD group (24.9%) and the NDRD group (19.0%). DKD was independently associated with diabetic retinopathy based on logistic regression analysis. The likelihood of DKD occurrence as defined by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative of the USA is applicable to Chinese patients with diabetes. Diabetic retinopathy was more prevalent in patients with DKD compared with patients with possible DKD or NDRD.

Efficacy and safety of losartan in treatment of hyperuricemia and posttransplantation erythrocytosis: results of a prospective, open, randomized, case-control study

BACKGROUND

Hyperuricemia and posttransplantation erythrocytosis (PTE) are frequent complications after kidney transplantation and are important risk factors for cardiovascular events. Losartan decreases serum uric acid and hemoglobin (Hb) concentrations and may be a useful agent for treatment of hyperuricemia and PTE.

OBJECTIVE

To evaluate the influence of losartan on serum creatinine (SCr), serum uric acid, and hemoglobin (Hb) concentrations in patients after kidney transplantation and to evaluate the safety profile of losartan in these patients.

PATIENTS AND METHODS

Sixty-six Han Chinese patients (43 men and 23 women; mean [SD] age, 40.45 [11.50] years) were enrolled in the study. All patients had undergone a first cadaveric donor kidney transplantation at least 3 months previously and had stable graft function with SCr concentration less than 176.8 micromol/L and Hb concentration greater than 110 g/L. The patients were divided into 2 groups (losartan group, n = 34; and control group, n = 32) according to the odevity of patient identification number. Patients in the losartan group received losartan, 50 mg/d; patients in the control group did not receive losartan. Each patient was followed up for 6 months.

RESULTS

Nine patients in the losartan group and 5 patients in the control group dropped out because of acute renal insufficiency, anemia, acute rejection, or poor compliance. The serum uric acid concentration in the losartan group continuously decreased at months 1, 2, 3, and 6 (P = .12, P = .01, P = .04, and P = .005 compared with baseline, and P = .02, P = .003, P = .02, and P = .006 compared with control), especially in the patients with hyperuricemia (P = .02, P < .001, P = .003, and P < .001 compared with baseline, and P = .02, P = .002, P = .02, and P = .002 compared with control). The Hb level in the losartan group decreased significantly at months 1, 2, 3, and 6 (P = .003, P < .001, P = .004, and P = 0.02 compared with baseline, and P = .001, P < .001, P = .001, and P = .005 compared with control), especially in patients with PTE. In patients without PTE, there was no significant decline in Hb concentration in the losartan group compared with baseline. There was no significant decline in estimated glomerular filtration rate in the losartan group.

CONCLUSIONS

Losartan may be an effective agent for treatment of hyperuricemia and PTE in Han Chinese patients after kidney transplantation. However, in some patients, losartan may not be safe.

Paroxysmal kinesigenic choreoathetosis: evidence of linkage to the pericentromeric region of chromosome 16 in four Chinese families

BACKGROUND

Paroxysmal kinesigenic choreoathetosis (PKC) is an autosomal dominant condition characterized by abnormal involuntary movements precipitated by sudden movement. The pericentromeric region of chromosome 16 has been linked to PKC by several reports. This study was to localize and identify PKC gene in four Chinese PKC families.

METHODS

Genetic linkage mapping with eight markers spanning chromosome 16p12-q13 was performed in 43 family members. Genome-wide single nucleotide polymorphism (SNP) scans were performed on four individuals in Family 1 in which infantile convulsion (IC) was co-inherited with PKC.

RESULTS

Individuals in Family 1 presented with both IC and paroxysmal choreoathetosis (ICCA), and Families 2, 3, and 4 presented only with PKC. Evidence for linkage was found with a maximum two-point LOD score of 4.89 for D16S690 (theta = 0.0) and a maximum multipoint LOD score was 5.34 between D16S3080 and D16S3136. Haplotype analysis showed the disease locus was between D16S3093 and D16S3057. A total of 84 SNPs spanned on 16q12.1-q13 was not segregated with the PKC phenotype, which defined an unlinked region from rs9933187 to rs8044753. Thus, the critical region of the PKC gene is across the pericentromeric region of chromosome 16, and most likely maps to a region of 20.5 Mb (6.2 cM) between D16S3093 and rs9933187 (16p11.2-q12.1).

CONCLUSION

The assignment of the locus for PKC to the pericentromeric region of chromosome 16 is confirmed and putatively narrowed in the present study.