A millisecond micromixer via single-bubble-based acoustic streaming

We present ultra-fast homogeneous mixing inside a microfluidic channel via single-bubble-based acoustic streaming. The device operates by trapping an air bubble within a "horse-shoe" structure located between two laminar flows inside a microchannel. Acoustic waves excite the trapped air bubble at its resonance frequency, resulting in acoustic streaming, which disrupts the laminar flows and triggers the two fluids to mix. Due to this technique's simple design, excellent mixing performance, and fast mixing speed (a few milliseconds), our single-bubble-based acoustic micromixer may prove useful for many biochemical studies and applications.

Tunable Liquid Gradient Refractive Index (L-GRIN) lens with two degrees of freedom

We report a tunable optofluidic microlens configuration named the Liquid Gradient Refractive Index (L-GRIN) lens for focusing light within a microfluidic device. The focusing of light was achieved through the gradient refractive index (GRIN) within the liquid medium, rather than via curved refractive lens surfaces. The diffusion of solute (CaCl(2)) between side-by-side co-injected microfluidic laminar flows was utilized to establish a hyperbolic secant (HS) refractive index profile to focus light. Tailoring the refractive index profile by adjusting the flow conditions enables not only tuning of the focal distance (translation mode), but also shifting of the output light direction (swing mode), a second degree of freedom that to our knowledge has yet to be accomplished for in-plane tunable microlenses. Advantages of the L-GRIN lens also include a low fluid consumption rate, competitive focusing performance, and high compatibility with existing microfluidic devices. This work provides a new strategy for developing integrative tunable microlenses for a variety of lab-on-a-chip applications.

Single-layer planar on-chip flow cytometer using microfluidic drifting based three-dimensional (3D) hydrodynamic focusing

In this work, we demonstrate an on-chip microfluidic flow cytometry system based on a three-dimensional (3D) hydrodynamic focusing technique, microfluidic drifting. By inducing Dean flow in a curved microfluidic channel, microfluidic drifting can be used to hydrodynamically focus cells or particles in the vertical direction and enables the 3D hydrodynamic focusing in a single-layer planar microfluidic device. Through theoretical calculation, numerical simulation, and experimental characterization, we found that the microfluidic drifting technique can be effectively applied to three-dimensionally focus microparticles with density and size equivalent to those of human CD4+ T lymphocytes. In addition, we developed a flow cytometry platform by integrating the 3D focusing device with a laser-induced fluorescence (LIF) detection system. The system was shown to provide effective high-throughput flow cytometry measurements at a rate of greater than 1700 cells s(-1).

Admixture mapping to identify breast cancer susceptibility loci in African American women

Abstract #2090

Background: The incidence of breast cancer in young women is higher in African American (AAW) compared to Caucasian (CW) and is associated with an aggressive phenotype, including high-grade, ER/PR and HER2 negative status and p53 positive characteristics. The aggressive tumor behavior and pathological features of AAW are also seen in women from the Bite of Biafra, an area of Western Africa that was the predominant source of the American slave trade. Similar tumor characteristics and shared ancestry suggest that population-specific molecular factors contribute to the aggressive tumor phenotypes associated with AAW. Therefore, a method of admixture mapping is proposed for this study. Admixture mapping is also known as mapping by admixture linkage disequilibrium. It assumes in a recent admixed population, if certain phenotype or the prevalence of a disease is mainly caused by one of the ancestral groups, the genetic variant can be located by the elevated ancestry from that group.
 Methods: Pathological characterization was performed histology specimens from 91 self-described AAW diagnosed with invasive breast cancer enrolled in the Clinical Breast Care Project. Genomic DNA was isolated and SNP data generated using the Affymetrix Mapping 100K arrays. African ancestry was determined using maximum likelihood estimator and chromosomal regions associated with disease identified using AncestryMap and AdmixMap.
 Results: The average age of diagnosis was 51 years. 25% of patients had poorly-differentiated, triple negative tumors. All 91 patients had significant African ancestry, with a mean level of Nigerian ancestry of 0.3857. Results from both AncestryMap and AdmixMap suggest loci on chromosomal regions 5q32.2, 9q13.1 and 17p13.3 are associated with the development of breast cancer.
 Discussion: Recently, admixture mapping was used to successfully identify a prostate cancer gene to chromosome 8q24 in African American men. Using a similar approach, we identified three chromosomal regions associated with the presence of invasive breast cancer in AAW with significant Western African ancestry. Of note, loss of 9q13 has been associated with poor survival, and allelic imbalance of 17p13.3 has been associated with loss of hormone receptor expression and poor prognosis. Thus, the use of admixture mapping may aid in the identification of genes involved in the development of the aggressive form of breast cancer associated with AAW.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2090.

Statins decrease the aberrant HLA-DR expression on thyrocytes from patients with Hashimoto's thyroiditis

Statins have been found to exert anti-inflammatory and immune modulatory effects. It seems likely that these drugs may improve thyroid function in patients with Hashimoto's thyroiditis (HT). The objective of our study was to investigate the effect of statins on HLA-DR (human leukocyte antigen D-related) expression of thyrocytes from patients with HT hypothyroidism. Thyroid tissues were obtained from surgical specimens. Thyrocytes were cultured in the presence or absence of IFN-gamma (50 ng/ml) with or without statins (simvastatin 10 microM or atorvastatin 10 microM) for 72 hours. HLA-DR expression was detected by flow cytometry. Normal thyrocytes were used for controls. HLA-DR expression of HT thyrocytes was much higher than that of normal thyrocytes (41.2+/-4.5% vs. 2.7+/-2.1%, p<0.01), which could be further increased by IFN-gamma stimulation in both groups (p<0.01). However, simvastatin and atorvastatin could significantly inhibit the "aberrant" HLA-DR expression on HT thyrocytes and decrease IFN-gamma- induced HLA-DR expression in both HT and normal thyroid cells (p<0.01). Statins can repress HLA-DR expression of HT thyrocytes, which might inhibit the subsequent lymphocyte activation and ameliorate the immune disturbance of HT.

Intensive glycemic control lowers plasma visfatin levels in patients with type 2 diabetes

Visfatin is an independent association factor for type 2 diabetes mellitus (T2DM). In order to evaluate the plasma visfatin levels and investigate whether plasma visfatin concentrations are altered by intensive glycemic control in patients with diabetes, we determined plasma visfatin concentrations and metabolic parameters in 53 newly diagnosed type 2 diabetic patients and 35 healthy controls. Visfatin levels were also investigated before and after intensive glycemic control for three months in subgroup of patients with T2DM. Plasma visfatin levels were significantly elevated in diabetic patients compared with healthy controls (p<0.001). Circulating visfatin concentration was associated with fasting plasma glucose (FPG), 2-hour OGTT plasma glucose (2hPG), HOMA-beta indexes (r=0.338, p=0.001; r=0.340, p=0.002; r=-0.296, p=0.006, respectively), but not with insulin sensitivity (HOMA-IR) or other metabolic or anthropometric parameters in all subjects. In addition, visfatin levels were also correlated with HbA1c levels in diabetic patients. Furthermore, visfatin concentrations reduced from 25.0+/-6.5 ng/ml at baseline to 20.3+/-4.7 ng/ml (p<0.01) after 3 months of intensive glycemic control, while HbA1c levels decreased from 9.0+/-1.8% to 6.2+/-0.7% (p<0.01). We conclude that the change of visfatin concentration may be a compensatory mechanism to ameliorate insulin deficiency due to pancreatic beta-cell dysfunction.

A novel c.545-546insG mutation in the loricrin gene correlates with a heterogeneous phenotype of loricrin keratoderma

BACKGROUND

Loricrin keratoderma (LK) is a group of congenital skin abnormalities characterized by the common features of honeycomb palmoplantar keratoderma and diffused ichthyosiform dermatosis. Earlier studies have shown that LK is associated with genetic defects of the loricrin gene.

OBJECTIVES

To determine the correlation between a loricrin mutation and a heterogeneous phenotype of loricrin keratoderma.

METHODS

We obtained DNA samples from a large family in which affected members showed more severe hyperkeratosis on the dorsal parts of their hands, mild palmoplantar keratoderma with no honeycomb-like manifestations and generalized ichthyosis. Screening of the loricrin gene was performed by direct sequencing of the entire coding region. Plasmids encoding the green fluorescent protein-tagged human loricrin were constructed and transferred to 293A cells for subcellular localization analyses.

RESULTS

Molecular analyses of the loricrin gene identified a novel insertion mutation c.545-546insG that resulted in a frameshift after codon 182. This mutation was predicted to produce a mutant protein with a frameshift of its C-terminal sequence of amino acids that embeds a newly generated nuclear localization signal (NLS), and to be 22 amino acids longer than the wild-type protein due to a delayed termination codon. The NLSs appear to result in an accumulation of mutant loricrin within nuclei.

CONCLUSIONS

Our results extend the repertoire of loricrin mutations underlying LK, provide further evidence that heterogeneous phenotypes of LK may be the result of genetic heterogeneity of loricrin mutations, and demonstrate that nuclear accumulation of mutant loricrin is due to the nuclear targeting sequences in the mutant C-terminus.

Abnormal AP-1 protein expression in primary cutaneous B-cell lymphomas

BACKGROUND

Primary cutaneous B-cell lymphoma (PCBCL) consists mainly of primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle centre lymphoma (PCFCL) and primary cutaneous large B-cell lymphoma, leg type (PCLBCL-LT). The activator protein 1 (AP-1) transcription factor includes JUN, FOS and other family members.

OBJECTIVES

To assess the expression pattern of AP-1 transcription factors in PCBCL.

METHODS

We analysed paraffin tissue sections from nine cases of PCMZL, seven PCFCL, six PCLBCL-LT and two unspecified PCBCL cases by using immunohistochemistry with antibodies against c-JUN, JUNB, JUND, c-FOS, RAF1, alphaPAK, CD30 and CCND1.

RESULTS

A positive staining for JUND (++) was observed in six cases of PCFCL (86%), five PCLBCL-LT (83%) and five PCMZL (56%). Positive CCND1 protein expression was present in four cases of PCLBCL-LT (67%), four PCFCL (57%) and four PCMZL (44%), and the two unspecified PCBCL cases. Expression of alphaPAK protein was seen in three cases of PCLBCL-LT (50%), two PCMZL (22%) and one PCFCL. However, c-JUN, c-FOS and RAF1 protein were rarely expressed in the PCBCL cases analysed; JUNB and CD30 protein expression was absent in these cases.

CONCLUSIONS

These findings suggest that the presence of abnormal AP-1 protein expression is associated with upregulation of JUND, CCND1 and alphaPAK and downregulation of JUNB in PCBCL.

Focusing microparticles in a microfluidic channel with standing surface acoustic waves (SSAW)

We introduce a novel on-chip microparticle focusing technique using standing surface acoustic waves (SSAW). Our method is simple, fast, dilution-free, and applicable to virtually any type of microparticle.

Assessing disease severity in late infantile neuronal ceroid lipofuscinosis using quantitative MR diffusion-weighted imaging

BACKGROUND AND PURPOSE

Late infantile neuronal ceroid lipofuscinosis (LINCL), a form of Batten disease, is a fatal neurodegenerative genetic disorder, diagnosed via DNA testing, that affects approximately 200 children in the United States at any one time. This study was conducted to evaluate whether quantitative data derived by diffusion-weighted MR imaging (DWI) techniques can supplement clinical disability scale information to provide a quantitative estimate of neurodegeneration, as well as disease progression and severity.

MATERIALS AND METHODS

This study prospectively analyzed 32 DWI examinations from 18 patients having confirmed LINCL at various stages of disease. A whole-brain apparent diffusion coefficient (ADC) histogram was fitted with a dual Gaussian function combined with a function designed to model voxels containing a partial volume fraction of brain parenchyma versus CSF. Previously published whole-brain ADC values of age-matched control subjects were compared with those of the LINCL patients. Correlations were tested between the peak ADC of the fitted histogram and patient age, disease severity, and a CNS disability scale adapted for LINCL.

RESULTS

ADC values assigned to brain parenchyma were higher than published ADC values for age-matched control subjects. ADC values between patients and control subjects began to differ at 5 years of age based on 95% confidence intervals. ADC values had a nearly equal correlation with patient age (R2=0.71) and disease duration (R2=0.68), whereas the correlation with the central nervous system disability scale (R2=0.27) was much weaker.

CONCLUSION

This study indicates that brain ADC values acquired using DWI may be used as an independent measure of disease severity and duration in LINCL.

Hydrodynamically tunable optofluidic cylindrical microlens

In this work, we report the design, fabrication, and characterization of a tunable optofluidic microlens that focuses light within a microfluidic device. The microlens is generated by the interface of two co-injected miscible fluids of different refractive indices, a 5 M CaCl(2) solution (n(D) = 1.445) and deionized (DI) water (n(D) = 1.335). When the liquids flow through a 90-degree curve in a microchannel, a centrifugal effect causes the fluidic interface to be distorted and the CaCl(2) solution bows outwards into the DI water portion. The bowed fluidic interface, coupled with the refractive index contrast between the two fluids, yields a reliable cylindrical microlens. The optical characteristics of the microlens are governed by the shape of the fluidic interface, which can be altered by simply changing the flow rate. Higher flow rates generate a microlens with larger curvature and hence shorter focal length. The changing of microlens profile is studied using both computational fluid dynamics (CFD) and confocal microscopy. The focusing effect is experimentally characterized through intensity measurements and image analysis of the focused light beam, and the experimental data are further confirmed by the results from a ray-tracing optical simulation. Our investigation reveals a simple, robust, and effective mechanism for integrating optofluidic tunable microlenses in lab-on-a-chip systems.

"Microfluidic drifting"--implementing three-dimensional hydrodynamic focusing with a single-layer planar microfluidic device

We introduce a novel fluid manipulation technique named "microfluidic drifting" to enable three-dimensional (3D) hydrodynamic focusing with a simple single-layer planar microfluidic device.

Neurological deterioration in late infantile neuronal ceroid lipofuscinosis

BACKGROUND

Late infantile neuronal ceroid lipofuscinosis (LINCL) is associated with progressive degeneration of the brain and retina starting in early childhood.

METHODS

Thirty-two individual neurologic, ophthalmologic, and CNS imaging (MRI and MRS) assessments of 18 children with LINCL were analyzed. Disease severity was followed by two rating scales, one previously established but modified to solely assess the brain and exclude the retinal disease (modified Hamburg LINCL scale), and a newly developed scale, with expanded evaluation of the CNS impairment (Weill Cornell LINCL scale).

RESULTS

For the 18 children, the Weill Cornell scale yielded a closer correlation with both age and time since initial clinical manifestation of the disease than did the modified Hamburg scale. There were no significant differences as a function of age or time since initial manifestation of the disease in the rating scales among the most frequent CLN2 mutations (G3556C, 56% of all alleles or C3670T, 22% of all alleles). Measurements of cortical MRS N-acetyl-aspartate content, MRI ventricular, gray matter and white matter volume, and cortical apparent diffusion coefficient correlated to a variable degree with the age of the children and the time since initial clinical manifestation of the disease. All imaging measurements correlated better with the Weill Cornell CNS scale compared to the modified Hamburg LINCL scale.

CONCLUSION

The data suggest that the Weill Cornell late infantile neuronal ceroid lipofuscinosis (LINCL) scale, together with several of the MRI measurements, may be useful in the assessment of severity and progression of LINCL and for the evaluation of novel therapeutic strategies.

Abnormal activator protein 1 transcription factor expression in CD30-positive cutaneous large-cell lymphomas

BACKGROUND

CD30+ cutaneous large-cell lymphomas (CLCL) represent a heterogeneous subgroup of skin lymphomas including primary cutaneous CD30+ anaplastic large-cell lymphoma (C-ALCL), lymphomatoid papulosis (LyP), transformed mycosis fungoides (T-MF) and Hodgkin's lymphoma (HL) with cutaneous involvement. The activator protein 1 (AP-1) transcription factor consists of JUN, FOS and other protein families. Recent studies have revealed upregulation of JUNB in both MF and C-ALCL and overexpression of JUNB and CD30 in systemic HL and ALCL.

OBJECTIVES

To assess systematically the expression pattern of AP-1 transcription factors in CLCL.

METHODS

We analysed paraffin tissue sections from 27 patients with LyP, 10 with C-ALCL, eight with T-MF and two with cutaneous HL by immunohistochemistry with antibodies against c-JUN, JUNB, JUND, c-FOS and RAF-1. We also stained samples from 10 patients with C-ALCL, seven with Sézary syndrome (SS), six with T-MF, three with cutaneous HL, two with LyP and control samples with total and phosphorylated mitogen-activated protein kinase (MAPK) antibodies. Results Positive staining for JUND (++) was observed in 13 cases of LyP (48%), 10 C-ALCL, six T-MF (75%) and two cutaneous HL cases. Positive JUNB protein expression was present in four cases of T-MF (50%), four C-ALCL (44%), three LyP (11%) and two cutaneous HL. Expression of total (p44/42) MAP kinase and phosphorylated p44/42 MAP kinase were detected in nine cases of C-ALCL (90%), seven SS (88%), five T-MF (89%) and three cutaneous HL. Most of these samples also showed positive staining for JUNB.

CONCLUSION

These results suggest the presence of abnormal AP-1 protein expression in CLCL, which may be relevant to CLCL.

Quantitative objective markers for upper and lower motor neuron dysfunction in ALS

OBJECTIVE

To investigate the value of objective biomarkers for upper (UMN) and lower (LMN) motor neuron involvement in ALS.

METHODS

We prospectively studied 64 patients with ALS and its subsets using clinical measures, proton MR spectroscopic imaging ((1)H MRSI), diffusion tensor imaging, transcranial magnetic stimulation, and the motor unit number estimation (MUNE) at baseline and every 3 months for 15 months and compared them with control subjects.

RESULTS

(1)H MRSI measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration were markedly reduced in ALS (p = 0.009) and all UMN syndromes combined (ALS, familial ALS [fALS], and primary lateral sclerosis; p = 0.03) vs control values. Central motor conduction time to the tibialis anterior was prolonged in ALS (p < 0.0005) and combined UMN syndromes (p = 0.001). MUNE was lower in ALS (p < 0.0005) and all LMN syndromes combined (ALS, fALS, and progressive muscular atrophy; p = 0.001) vs controls. All objective markers correlated well with the ALS Functional Rating Scale-Revised, finger and foot tapping, and strength testing, suggesting these markers related to disease activity. Regarding changes over time, MUNE changed rapidly, whereas neuroimaging markers changed more slowly and did not significantly differ from baseline.

CONCLUSIONS

(1)H MR spectroscopic imaging measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration and ratio of NAA to creatine, central motor conduction time to the tibialis anterior, and motor unit number estimation significantly differed between ALS, its subsets, and control subjects, suggesting they have potential to provide insight into the pathobiology of these disorders.

Development of an integrated enzymatic treatment system for phenolic waste streams

An integrated enzymatic treatment system, which includes Coprinus cinereus peroxidase (CIP) production, processing, and usage in batch or plug flow reactors, is being developed to remove phenolic compounds from the aqueous waste streams. CIP production at bench scale yielded a maximum growth medium activity of approximately 60 U CIP ml(-1). A CIP enzyme solution was prepared for use in treatment by successive filtration steps. This yielded a 4.5-fold increase in enzyme activity, with 87% enzyme activity recovery, and 83% reduction in the solution's Chemical Oxygen Demand. The purity of CIP was observed to have no effect on the ability of the enzyme to remove phenol from the aqueous solutions within the range of enzyme solution purities tested. Contrary to observations reported for phenol removal from buffered solutions, the addition of polyethylene glycol to non-buffered reaction solutions had no positive effect on the phenol removal accomplished at pH 7 in these experiments. The efficiency of enzyme use in a plug flow reactor was improved by step additions of CIP and H2O2.