Low power four wave mixing in an integrated, micro-ring resonator with Q = 1.2 million

We demonstrate efficient, low power, continuous-wave four-wave mixing in the C-band, using a high index doped silica glass micro ring resonator having a Q-factor of 1.2 million. A record high conversion efficiency for this kind of device is achieved over a bandwidth of 20 nm. We show theoretically that the characteristic low dispersion enables phase-matching over a tuning range > 160 nm.

Metabolic and histological features of non-alcoholic fatty liver disease patients with different serum alanine aminotransferase levels

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. Serum alanine aminotransferase (ALT) level is commonly performed to monitor NAFLD patients, but its clinical relevance is unclear.

AIM

To evaluate the metabolic and histological features of NAFLD patients with different ALT levels.

METHODS

A total of 173 consecutive patients with biopsy-proven NAFLD were studied. Patients with persistently normal ALT and those with abnormal ALT were compared.

RESULTS

Patients with persistently normal ALT had lower steatosis grade than patients with abnormal ALT, but they had similar degree of lobular inflammation, ballooning and fibrosis. Among 19 patients with ALT below 0.5 times the upper limit of normal (ULN) at the time of liver biopsies, 8 (42%) and 3 (16%) had steatohepatitis and significant fibrosis respectively. The within-patient coefficient of variance was similarly high in patients with simple steatosis and steatohepatitis (33.5). Age and glucose, but not ALT, were independent factors associated with significant fibrosis.

DISCUSSION

Metabolic factors, but not ALT, are associated with histological severity. Patients with ALT < 0.5 x ULN may still have non-alcoholic steatohepatitis (NASH) and significant fibrosis. Evaluation of NAFLD patients should be based on metabolic risk factors, but not ALT level.

X-linked distal hereditary motor neuropathy maps to the DSMAX locus on chromosome Xq13.1-q21

OBJECTIVE

To clinically characterize and map the gene locus in a three-generation family with an X-linked adult-onset distal hereditary motor neuropathy.

METHODS

Microsatellite markers spanning the juvenile distal spinal muscular atrophy (DSMAX) locus were genotyped and analyzed using genetic linkage analysis. The promoter, untranslated and coding region of the gap junction beta1 (GJB1) gene was sequenced. Nine positional candidate genes were screened for disease mutations using high-resolution melt (HRM) analysis.

RESULTS

The family showed significant linkage to markers on chromosome Xq13.1-q21. Haplotype construction revealed a disease-associated haplotype between the markers DXS991 and DX5990. Sequence analysis excluded pathogenic changes in the coding and promoter regions of the GJB1 gene. Additional fine mapping in the family refined the DSMAX locus to a 1.44-cM interval between DXS8046 and DXS8114. HRM analysis did not identify disease-associated mutations in the coding region of nine candidate genes.

CONCLUSION

We have identified a family with adult-onset distal hereditary motor neuropathy that refines the locus reported for juvenile distal spinal muscular atrophy (DSMAX) on chromosome Xq13.1-q21. Exclusion of mutations in the coding and regulatory region of the GJB1 gene eliminated the CMTX1 locus as a cause of disease in this family. Nine positional candidate genes in the refined interval underwent mutation analysis and were eliminated as the pathogenic cause of DSMAX in this family. The syndrome in this family may be allelic to the juvenile distal spinal muscular atrophy first reported at this locus.

Synthetic orocutaneous stimulation entrains preterm infants with feeding difficulties to suck

BACKGROUND

Prematurity can disrupt the development of a specialized neural circuit known as suck central pattern generator (sCPG), which often leads to poor feeding skills. The extent to which suck can be entrained using a synthetically patterned orocutaneous input to promote its development in preterm infants who lack a functional suck is unknown.

OBJECTIVE

To evaluate the effects of a new motorized 'pulsating' pacifier capable of entraining the sCPG in tube-fed premature infants who lack a functional suck and exhibit feeding disorders.

METHODS

Prospective cohort study of 31 preterm infants assigned to either the oral patterned entrainment intervention (study) or non-treated (controls) group, matched by gestational age, birth weight, oxygen supplementation history and oral feed status. Study infants received a daily regimen of orocutaneous pulse trains through a pneumatically controlled silicone pacifier concurrent with gavage feeds.

RESULTS

The patterned orocutaneous stimulus was highly effective in accelerating the development of non-nutritive suck (NNS) in preterm infants. A repeated-measure multivariate analysis of covariance revealed significant increases in minute rates for total oral compressions, NNS bursts, and NNS cycles, suck cycles per burst, and the ratiometric measure of NNS cycles as a percentage of total ororhythmic output. Moreover, study infants also manifest significantly greater success at achieving oral feeds, surpassing their control counterparts by a factor of 3.1 x (72.8% daily oral feed versus 23.3% daily oral feed, respectively).

CONCLUSION

Functional expression of the sCPG among preterm infants who lack an organized suck can be induced through the delivery of synthetically patterned orocutaneous pulse trains. The rapid emergence of NNS in treated infants is accompanied by a significant increase in the proportion of nutrient taken orally.

Polyelectrolyte behavior and kinetics of aminoacyl-tRNA on the ribosome

The torque acting on cognate (three base pairs that are matched) "ternary complex" consisting of elongation factor-Tu, guanosine-5'-triphosphate GTP, and aminoacyl-transfer RNA due to induced wrapping of the 30S subunit of the ribosome and the speed with which the ternary complex samples the space allowed by diffusion is determined. Under appropriate conditions, mode coupling speeds up the barrier crossing rate for cognate relative to near-cognate ternary complexes. We determine the flexibility of the ternary complex relative to transfer RNA (tRNA) by a coarse-grained model. We predict the magnesium binding sites in the ternary complex at low magnesium concentration and unravel the nature of the interaction energy of magnesium with site-specific tRNAPhe bases.

266. Loss of betaglycan expression contributes to malignant properties of human granulosa tumour cells

Betaglycan is a type III TGF-β receptor that binds to both inhibin and TGF-β with high affinity and determines cellular sensitivity to these ligands. Previous studies have suggested that betaglycan acts as a tumour suppressor in certain human epithelial cancers. However, the roles of betaglycan in ovarian granulosa cell tumours (GCTs) are poorly understood. The objective of this study was to determine whether human GCTs exhibit betaglycan expression, and if so, what impact this receptor has on tumour biology. Real-time PCR was used to quantify betaglycan transcripts in human GCTs (n = 18) and normal premenopausal ovaries (n = 11). This analysis established that GCTs exhibited a significant 2-fold reduction in mean betaglycan mRNA levels as compared with the normal ovary (P < 0.05). Similarly, two human GCT cell lines, the KGN and COV434, exhibited low betaglycan expression and poor responsiveness to TGF-β and inhibin in luciferase reporter assays. Stable transfection of GCT cell lines with a wildtype betaglycan (WT-BG) expression plasmid conveyed ligand responsiveness. FACS analysis was used to examine cell cycle progression and cell death in the GCT cell lines. This analysis revealed that WT-BG had no effect on the number of cells cycling or undergoing apoptosis. However, WT-BG significantly increased the adhesion of COV434 (P < 0.05) and KGN (P < 0.0001) cells to collagen IV and fibronectin, decreased cellular invasion through Matrigel COV434 (50%) and KGN (75%), and inhibited wound healing COV434 (70%) and KGN (80%). Collectively, the data establish that betaglycan is an important regulator of granulosa cell biology and suggest that a deficiency in betaglycan contributes to the pathogenesis of granulosa cell cancer. The work further suggests a role for betaglycan in the prevention of tumour invasion, possibly by increasing the adhesion of granulosa cells to matrix components. Supported by: the NHMRC of Australia (RegKeys 338516; 241000; 441101; 388904).

Cigarette smoke condensate inhibits ENaC alpha-subunit expression in lung epithelial cells

Cigarette smoke has been associated with lung fluid accumulation and increased risk of acute respiratory distress syndrome. It was postulated that ENaC alpha-subunit, which plays a critical role in lung fluid absorption, is affected by cigarette smoke. Cigarette smoke condensate (CSC) was used to treat a human lung epithelial cell line. ENaC alpha-subunit expression was measured using immunoblotting, quantitative PCR and promoter-reporter assays. The current authors found that CSC, without affecting cell survival, suppressed alpha-subunit expression at the transcriptional level in a dose- and time-dependent fashion. This suppression is neither related to nicotine nor due to an increase of hydrogen peroxide levels in CSC-treated cells. CSC also suppressed alpha-subunit core promoter activity. Dexamethasone, which activates the core promoter, was able to attenuate the inhibitory effect of CSC. However, in the presence of CSC, dexamethasone was unable to elicit a full-scale activation of alpha-subunit expression. This inhibition of dexamethasone was partially reversed by withdrawal of CSC. The present results demonstrate that cigarette smoke condensate inhibits ENaC alpha-subunit expression at the transcriptional level through its promoter. This inhibition could be reversed by dexamethasone. The results also suggest that higher doses of dexamethasone may be needed to activate alpha-subunit expression in smokers' lungs compared with nonsmokers' lungs, and that quitting smoking might improve the effectiveness of dexamethasone.

XmAb Fc engineered anti-CD19 monoclonal antibodies with enhanced in vitro efficacy against multiple lymphoma cell lines

3021

Background: CD19 is a pan-B cell surface receptor that is expressed from early stages of pre-B cell development through terminal differentiation into plasma cells. It is an attractive immunotherapy target for cancers of lymphoid origin since it is also expressed on the vast majority of Non-Hodgkin Lymphoma (NHL) cells as well as some leukemias. Despite major improvements in response rates and progression free survival the majority of NHL patients will relapse under the current combination chemotherapy with anti-CD20. Thus salvage regimens with new non-cross resistant antibody therapies are warranted. Methods: We employ our XmAb antibody engineering technology to increase the affinity of IgG antibodies for Fc gamma receptors (FcγR), improve the effector function of antibodies, and significantly increases their antitumor potency; we also we humanize and affinity mature such antibodies. Results: The XmAb technology was applied to a humanized anti-CD19 antibody to engineer a variant with significantly enhanced (10- to 100-fold) antibody-dependent cell-mediated cytotoxicity (ADCC). The resulting XmAb CD19 variant was assayed for ADCC against multiple cell lines representative of follicular lymphoma (FL), chronic lymphocytic leukemia (CLL), B-cell acute lymphoblastic leukemia (B-ALL), mantle cell lymphoma (MCL), hairy cell leukemia (HCL), chronic myelogenous leukemia (CML), and Burkitt’s lymphoma (BL). The ADCC activity of the XmAb CD19 was in striking contrast to a wild type IgG1 version of the antibody that mediates little ADCC. Moreover, ADCC potency and efficacy of the anti-CD19 Fc variant antibody were superior to that of rituximab: CLL - 10- and 1.5-fold higher, ALL - 10- and 100-fold higher, and HCL - 6- and 1.2-fold higher, respectively. Further, we observed no correlation between ADCC and antigen expression based on the measured cell surface density of CD19 for these cell lines. Conclusions: The increased affinity for FcγRs exhibited by the anti-CD19 Fc variant antibody overcomes much of the dependence of cytotoxicity on surface antigen density. Our data suggest that the anti-CD19 Fc variant antibody engineered for increased effector function could be a promising next-generation NHL immunotherapeutic.

No significant financial relationships to disclose.

Insulin-like growth factor, insulin-like growth factor-binding protein-4, and pregnancy-associated plasma protein-A gene expression in human granulosa cell tumors

The insulin-like growth factor (IGF) system plays an important role in folliculogenesis. It is also thought to contribute to the pathogenesis of many cancers, including those of the ovarian epithelium. In the human follicle, the predominant IGF is IGF-II and its actions are modulated by insulin-like growth factor-binding protein-4 (IGFBP-4), the IGFBP-4 protease, and the pregnancy-associated plasma protein-A (PAPP-A). These peptide components are synthesized by the granulosa cells of the developing follicle. The aim of this study was to characterize the expression of these components of the IGF system in granulosa cell tumors (GCT) of the ovary. IGF-I, IGF-II, IGFBP-4, and PAPP-A gene expression was determined in a panel of GCT and compared to the levels in normal ovary and in epithelial ovarian tumors. Although both the IGF-I and IGF-II genes were expressed in the GCT, the levels were lower than in the other tissue groups. IGFBP-4 expression was also low in the GCT, whereas PAPP-A gene expression was highest in the GCT. These findings were unexpected given the prominent role this signaling system plays in normal granulosa cells. In conclusion, these observations suggest that the IGF system may have a limited role in the pathogenesis of GCT with PAPP-A subserving a function other than IGFBP-4 proteolysis.

Parametric amplification of matter waves in periodically translated optical lattices

We observe the sudden growth of small classes of Bloch waves from atomic Bose-Einstein condensates held in periodically translated optical lattices. The effect is explained by narrowband parametric amplification of Bloch waves from noise, due to phase-matched scattering of atom pairs out of the condensate. Amplification occurs above a well-defined modulation threshold, described by dynamic shaping of single-particle band structure.

Direct measurement of acid permeation into rat oesophagus

BACKGROUND AND AIMS

The early responses of the oesophageal mucosa to acid perfusion may predict subsequent pathology. Mucosal responses to luminal acid may result either from acid permeating through the mucosa or from other unknown transduction mechanisms. In order to better understand the dynamics of acid permeation into the oesophageal mucosa, we measured interstitial pH (pH(int)) of the oesophageal basal epithelial layer, pre-epithelial layer thickness, and blood flow in rats in vivo during luminal acid challenge. A novel confocal microscopic technique was used in vitro to measure pH(int) from defined cellular sites in response to luminal and basolateral acidification.

METHODS

5-(and-6)-Carboxyfluorescein (CF) and carboxy-seminapthorhodofluor-1 (SNARF-1) fluorescence was used to measure pH(int) by conventional and confocal microscopy, respectively, in urethane anaesthetised rats. Pre-epithelial layer thickness was measured optically with carbon particles as markers. Blood flow was measured with laser Doppler flowmetry.

RESULTS

Luminal acidification failed to alter pH(int) in vivo and in vitro, but pH(int) was lowered by modest serosal acidification. Pre-epithelial layer thickness and blood flow increased significantly during luminal surface acid perfusion. Indomethacin had no effect on any acid related response.

CONCLUSION

In this first dynamic measurement of oesophageal acid permeation and pre-epithelial layer thickness, pH(int) was preserved in spite of high luminal acidity by two complementary techniques. Despite the apparent permeability barrier to acid permeation, oesophageal blood flow and thickness responded to luminal acid perfusion.

FSH-regulated gene expression profiles in ovarian tumours and normal ovaries

Development, growth and function of the ovary are controlled by endocrine and paracrine signals. These may also influence the development of ovarian cancer. The aim of this study was to identify the key molecular markers of the unregulated growth and hormone synthesis seen in ovarian tumours, particularly in granulosa cell tumours (GCT). Genes used in this study were chosen on the basis of our understanding of growth and differentiation in the normal ovary. We sought to define the patterns of gene expression in a panel of epithelial and stromal ovarian tumours. Expression was determined by RT-PCR using gene-specific primers for the FSH receptor (FSHR); the FSH early response genes: regulatory subunit of protein kinase A (RII-beta), cyclin D2 (cycD2) and sgk; and late response markers: cyclooxygenase-2 (COX-2) and the LH receptor (LHR). The GCT had high expression of FSHR compared with normal ovaries and the other tumours. cycD2 and RII-beta and COX-2 genes were also highly expressed in the GCT. sgk and LHR expression was lower in all of the tumours than in normal ovaries. Serous cystadenocarcinomas also had an unexpectedly high expression of COX-2. Comparison of the gene expression profiles between each tumour group suggests a molecular phenotype for GCT that is similar to that reported for FSH stimulated pre-ovulatory granulosa cells.

Computerised clinical pathway as process quality improvement tool

Experiences from other industries show that process quality improvement (PQI) is far more effective than product quality assurance in ensuring quality outputs and cost savings. The PQI approach is becoming more important to the healthcare industry as healthcare professionals struggle to cope with increasing demands for productivity gains, the raising patient acuity and need to curtail the large number of adverse medical events. This paper presents a continuous process quality improvement operational model for healthcare quality improvement and operationalization of the model through the implementation of a computerised clinical pathway management system (CCPMS). It also reports on a small-scale evaluative study conducted to assess the effectiveness of the PQI approach using the CCMPS prototype.

[Use of microsatellites in zygosity diagnosis of twins]

OBJECTIVE

To diagnose zygosity of twins by microsatellite polymorphism.

METHODS

One hundred and eighty-four samples, including 69 pairs of twins with the same gender and 6 pairs of twins with different gender were recruited. Seventeen sib pairs were also collected for controls. Nine highly polymorphic microsatellite loci were amplified by polymerase chain reaction (PCR) using fluorescence-labeled primers and the products were sized by automated fragment analysis after electrophoresis and laser detection. Zygosity was diagnosed by comparing the concordance of the genotype of the 9 markers.

RESULTS

Sixty-three pairs of monozygotic (MZ) and 12 pairs of dizygotic (DZ) twins were assigned their zygosity by comparison of polymorphism of 9 microsatellite loci. Within each of the 63 monozygotic (MZ) pairs there was complete concordance. However, within each of the 12 dizygotic pairs and other 17 sib pairs, discordant loci were found. With five or six markers, the probability that any twin pair was MZ if all markers were concordant was 99% or 99.6%, respectively. With all the nine markers, the probability that any twin pair was MZ if all markers were concordant was 99.95%.

CONCLUSION

The technology of gene scan and genotyping provides a rapid and reliable approach to zygosity detection.