Motion Blur Microscopy

Imaging and characterizing the dynamics of cellular adhesion in blood samples is of fundamental importance in understanding biological function. In vitro microscopy methods are widely used for this task, but typically require diluting the blood with a buffer to allow for transmission of light. However whole blood provides crucial mechanical and chemical signaling cues that influence adhesion dynamics, which means that conventional approaches lack the full physiological complexity of living microvasculature. We propose to overcome this challenge by a new in vitro imaging method which we call motion blur microscopy (MBM). By decreasing the source light intensity and increasing the integration time during imaging, flowing cells are blurred, allowing us to identify adhered cells. Combined with an automated analysis using machine learning, we can for the first time reliably image cell interactions in microfluidic channels during whole blood flow. MBM provides a low cost, easy to implement alternative to intravital microscopy, the in vivo approach for studying how the whole blood environment shapes adhesion dynamics. We demonstrate the method's reproducibility and accuracy in two example systems where understanding cell interactions, adhesion, and motility is crucial-sickle red blood cells adhering to laminin, and CAR-T cells adhering to E-selectin. We illustrate the wide range of data types that can be extracted from this approach, including distributions of cell size and eccentricity, adhesion durations, trajectories and velocities of adhered cells moving on a functionalized surface, as well as correlations among these different features at the single cell level. In all cases MBM allows for rapid collection and processing of large data sets, ranging from thousands to hundreds of thousands of individual adhesion events. The method is generalizable to study adhesion mechanisms in a variety of diseases, including cancer, blood disorders, thrombosis, inflammatory and autoimmune diseases, as well as providing rich datasets for theoretical modeling of adhesion dynamics.

Posterior open wound healing in immediate implant placement using reactive soft tissue versus absorbable collagen sponge: a retrospective cohort study

The soft and hard tissue healing of open wounds in immediate implant placement are yet to be explored. The aim of this study was to compare the clinical outcomes of open wound healing using reactive soft tissue (RST) and absorbable collagen sponge (ACS). Forty implants placed immediately in posterior sockets were included; autologous RST was used in 20 and ACS substitute was used in 20. Soft tissue healing was primarily assessed through a novel scoring system and the evaluation of gingival recession. The horizontal bone width (HBW) and interproximal marginal bone level (MBL) were measured on radiographs to observe the hard tissue healing. No significant difference in total soft tissue healing score was observed at 2 weeks postoperatively. Notably, the ACS group showed better tissue colour (P = 0.016) but worse fibrous repair (P = 0.043) scores than the RST group. Gingival recession levels were comparable in the two groups, both before tooth extraction and after placement of the restoration. Regarding hard tissue, HBW and MBL changes showed no intergroup differences. Within the limitations of this study, both RST and ACS seemed effective for open wound closure, achieving ideal soft and hard tissue healing in immediate implant placement.

Rapid measurement of hemoglobin-oxygen dissociation by leveraging Bohr effect and Soret band bathochromic shift

Oxygen (O2) binds to hemoglobin (Hb) in the lungs and is then released (dissociated) in the tissues. The Bohr effect is a physiological mechanism that governs the affinity of Hb for O2 based on pH, where a lower pH results in a lower Hb-O2 affinity and higher Hb-O2 dissociation. Hb-O2 affinity and dissociation are crucial for maintaining aerobic metabolism in cells and tissues. Despite its vital role in human physiology, Hb-O2 dissociation measurement is underutilized in basic research and in clinical laboratories, primarily due to the technical complexity and limited throughput of existing methods. We present a rapid Hb-O2 dissociation measurement approach by leveraging the Bohr effect and detecting the optical shift in the Soret band that corresponds to the light absorption by the heme group in Hb. This new method reduces Hb-O2 dissociation measurement time from hours to minutes. We show that Hb deoxygenation can be accelerated chemically at the optimal pH of 6.9. We show that time and pH-controlled deoxygenation of Hb results in rapid and distinct conformational changes in its tertiary structure. These molecular conformational changes are manifested as significant, detectable shifts in Hb's optical absorption spectrum, particularly in the characteristic Soret band (414 nm). We extensively validated the method by testing human blood samples containing normal Hb and Hb variants. We show that rapid Hb-O2 dissociation can be used to screen for and detect Hb-O2 affinity disorders and to evaluate the function and efficacy of Hb-modifying therapies. The ubiquity of optical absorption spectrophotometers positions this approach as an accessible, rapid, and accurate Hb-O2 dissociation measurement method for basic research and clinical use. We anticipate this method's broad adoption will democratize the diagnosis and prognosis of Hb disorders, such as sickle cell disease. Further, this method has the potential to transform the research and development of new targeted and genome-editing-based therapies that aim to modify or improve Hb-O2 affinity.

Exploring the role of histone deacetylase inhibitors in cancer development and therapeutic potential

The process of acetylation and deacetylation of histones within the nucleus operates within a dynamic equilibrium. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) collaboratively and precisely regulate normal gene transcription and expression. Any disorder in the activity of HATs/HDACs can lead to uncontrolled gene expression, consequently resulting in tumorigenesis. Histone deacetylase inhibitors (HDACIs) have the capacity to block the cell cycle, thereby restraining tumor cell proliferation and tumor growth. Also, HDACIs exhibit a significant capability to diminish the expression of apoptosis protein inhibitors such as Bcl-2 and B-cell lymphoma-extra-large (Bcl-xL), while concurrently up-regulating pro-apoptotic proteins such as Bax, Bad, and Bim. Also, HDACIs demonstrate the ability to inhibit tumor cell angiogenesis. Representing a new category of targeted anti-cancer therapeutics, HDACIs possess the capability to restore the expression of tumor suppressor genes, induce apoptosis, and stimulate cell differentiation. Additionally, they exert anti-cancer effects through diverse pathways both in vivo and in vitro, thereby presenting promising prospects in tumor therapy. This review delves into the involvement of HDACs in cancer pathology and the therapeutic potential of HDACIs as emerging drugs in cancer treatment.

Beta-defensin index: A functional biomarker for oral cancer detection

There is an unmet clinical need for a non-invasive and cost-effective test for oral squamous cell carcinoma (OSCC) that informs clinicians when a biopsy is warranted. Human beta-defensin 3 (hBD-3), an epithelial cell-derived anti-microbial peptide, is pro-tumorigenic and overexpressed in early-stage OSCC compared to hBD-2. We validate this expression dichotomy in carcinoma in situ and OSCC lesions using immunofluorescence microscopy and flow cytometry. The proportion of hBD-3/hBD-2 levels in non-invasively collected lesional cells compared to contralateral normal cells, obtained by ELISA, generates the beta-defensin index (BDI). Proof-of-principle and blinded discovery studies demonstrate that BDI discriminates OSCC from benign lesions. A multi-center validation study shows sensitivity and specificity values of 98.2% (95% confidence interval [CI] 90.3-99.9) and 82.6% (95% CI 68.6-92.2), respectively. A proof-of-principle study shows that BDI is adaptable to a point-of-care assay using microfluidics. We propose that BDI may fulfill a major unmet need in low-socioeconomic countries where pathology services are lacking.

A human lung alveolus-on-a-chip model of acute radiation-induced lung injury

Acute exposure to high-dose gamma radiation due to radiological disasters or cancer radiotherapy can result in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium (Lung Alveolus Chip) is used to model acute RILI in vitro. Both lung epithelium and endothelium exhibit DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage is observed in the endothelium. The radiation dose sensitivity observed on-chip is more like the human lung than animal preclinical models. The Alveolus Chip is also used to evaluate the potential ability of two drugs - lovastatin and prednisolone - to suppress the effects of acute RILI. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative for studying the molecular basis of acute RILI and may be useful for evaluation of new radiation countermeasure therapeutics.

Catch bonds in sickle cell disease: Shear-enhanced adhesion of red blood cells to laminin

Could the phenomenon of catch bonding-force-strengthened cellular adhesion-play a role in sickle cell disease, where abnormal red blood cell (RBC) adhesion obstructs blood flow? Here, we investigate the dynamics of sickle RBCs adhering to a surface functionalized with the protein laminin (a component of the extracellular matrix around blood vessels) under physiologically relevant microscale flow. First, using total internal reflectance microscopy we characterize the spatial fluctuations of the RBC membrane above the laminin surface before detachment. The complex dynamics we observe suggest the possibility of catch bonding, where the mean detachment time of the cell from the surface initially increases to a maximum and then decreases as a function of shear force. We next conduct a series of shear-induced detachment experiments on blood samples from 25 sickle cell disease patients, quantifying the number and duration of adhered cells under both sudden force jumps and linear force ramps. The experiments reveal that a subset of patients does indeed exhibit catch bonding. By fitting the data to a theoretical model of the bond dynamics, we can extract the mean bond lifetime versus force for each patient. The results show a striking heterogeneity among patients, both in terms of the qualitative behavior (whether or not there is catch bonding) and in the magnitudes of the lifetimes. Patients with large bond lifetimes at physiological forces are more likely to have certain adverse clinical features, like a diagnosis of pulmonary arterial hypertension and intracardiac shunts. By introducing an in vitro platform for fully characterizing RBC-laminin adhesion dynamics, our approach could contribute to the development of patient-specific antiadhesive therapies for sickle cell disease. The experimental setup is also easily generalizable to studying adhesion dynamics in other cell types, for example, leukocytes or cancer cells, and can incorporate disease-relevant environmental conditions like oxygen deprivation.

Sickle red blood cell-derived extracellular vesicles activate endothelial cells and enhance sickle red cell adhesion mediated by von Willebrand factor

Endothelial activation and sickle red blood cell (RBC) adhesion are central to the pathogenesis of sickle cell disease (SCD). Quantitatively, RBC-derived extracellular vesicles (REVs) are more abundant from SS RBCs compared with healthy RBCs (AA RBCs). Sickle RBC-derived REVs (SS REVs) are known to promote endothelial cell (EC) activation through cell signalling and transcriptional regulation at longer terms. However, the SS REV-mediated short-term non-transcriptional response of EC is unclear. Here, we examined the impact of SS REVs on acute microvascular EC activation and RBC adhesion at 2 h. Compared with AA REVs, SS REVs promoted human pulmonary microvascular ECs (HPMEC) activation indicated by increased von Willebrand factor (VWF) expression. Under microfluidic conditions, we found abnormal SS RBC adhesion to HPMECs exposed to SS REVs. This enhanced SS RBC adhesion was reduced by haeme binding protein haemopexin or VWF cleaving protease ADAMTS13 to a level similar to HPMECs treated with AA REVs. Consistent with these observations, haemin- or SS REV-induced microvascular stasis in SS mice with implanted dorsal skin-fold chambers that was inhibited by ADAMTS13. The adhesion induced by SS REVs was variable and was higher with SS RBCs from patients with increased markers of haemolysis (lactate dehydrogenase and reticulocyte count) or a concomitant clinical diagnosis of deep vein thrombosis. Our results emphasise the critical contribution made by REVs to the pathophysiology of SCD by triggering acute microvascular EC activation and abnormal RBC adhesion. These findings may help to better understand acute pathophysiological mechanism of SCD and thereby the development of new treatment strategies using VWF as a potential target.

A microfluidic device for assessment of E-selectin-mediated neutrophil recruitment to inflamed endothelium and prediction of therapeutic response in sickle cell disease

Neutrophil recruitment to the inflamed endothelium is a multistep process and is of utmost importance in the development of the hallmark vaso-occlusive crisis in sickle cell disease (SCD). However, there lacks a standardized, clinically feasible approach for assessing neutrophil recruitment to the inflamed endothelium for individualized risk stratification and therapeutic response prediction in SCD. Here, we describe a microfluidic device functionalized with E-selectin, a critical endothelial receptor for the neutrophil recruitment process, as a strategy to assess neutrophil binding under physiologic flow in normoxia and clinically relevant hypoxia in SCD. We show that hypoxia significantly enhances neutrophil binding to E-selectin and promotes the formation of neutrophil-platelet aggregates. Moreover, we identified two distinct patient populations: a more severe clinical phenotype with elevated lactate dehydrogenase levels and absolute reticulocyte counts but lowered fetal hemoglobin levels associated with constitutively less neutrophil binding to E-selectin. Mechanistically, we demonstrate that the extent of neutrophil activation correlates with membrane L-selectin shedding, resulting in the loss of ligand interaction sites with E-selectin. We also show that inhibition of E-selectin significantly reduces leukocyte recruitment to activated endothelial cells. Our findings add mechanistic insight into neutrophil-endothelial interactions under hypoxia and provide a clinically feasible means for assessing neutrophil binding to E-selectin using clinical whole blood samples, which can help guide therapeutic decisions for SCD patients.

PUM1 mediates the posttranscriptional regulation of human fetal hemoglobin

The fetal-to-adult hemoglobin switching at about the time of birth involves a shift in expression from γ-globin to β-globin in erythroid cells. Effective re-expression of fetal γ-globin can ameliorate sickle cell anemia and β-thalassemia. Despite the physiological and clinical relevance of this switch, its posttranscriptional regulation is poorly understood. Here, we identify Pumilo 1 (PUM1), an RNA-binding protein with no previously reported functions in erythropoiesis, as a direct posttranscriptional regulator of β-globin switching. PUM1, whose expression is regulated by the erythroid master transcription factor erythroid Krüppel-like factor (EKLF/KLF1), peaks during erythroid differentiation, binds γ-globin messenger RNA (mRNA), and reduces γ-globin (HBG1) mRNA stability and translational efficiency, which culminates in reduced γ-globin protein levels. Knockdown of PUM1 leads to a robust increase in fetal hemoglobin (∼22% HbF) without affecting β-globin levels in human erythroid cells. Importantly, targeting PUM1 does not limit the progression of erythropoiesis, which provides a potentially safe and effective treatment strategy for sickle cell anemia and β-thalassemia. In support of this idea, we report elevated levels of HbF in the absence of anemia in an individual with a novel heterozygous PUM1 mutation in the RNA-binding domain (p.(His1090Profs∗16); c.3267_3270delTCAC), which suggests that PUM1-mediated posttranscriptional regulation is a critical player during human hemoglobin switching.

OcclusionChip: A functional microcapillary occlusion assay complementary to ektacytometry for detection of small-fraction red blood cells with abnormal deformability

Red blood cell (RBC) deformability is a valuable hemorheological biomarker that can be used to assess the clinical status and response to therapy of individuals with sickle cell disease (SCD). RBC deformability has been measured by ektacytometry for decades, which uses shear or osmolar stress. However, ektacytometry is a population based measurement that does not detect small-fractions of abnormal RBCs. A single cell-based, functional RBC deformability assay would complement ektacytometry and provide additional information. Here, we tested the relative merits of the OcclusionChip, which measures RBC deformability by microcapillary occlusion, and ektacytometry. We tested samples containing glutaraldehyde-stiffened RBCs for up to 1% volume fraction; ektacytometry detected no significant change in Elongation Index (EI), while the OcclusionChip showed significant differences in Occlusion Index (OI). OcclusionChip detected a significant increase in OI in RBCs from an individual with sickle cell trait (SCT) and from a subject with SCD who received allogeneic hematopoietic stem cell transplant (HSCT), as the sample was taken from normoxic (pO2:159 mmHg) to physiologic hypoxic (pO2:45 mmHg) conditions. Oxygen gradient ektacytometry detected no difference in EI for SCT or HSCT. These results suggest that the single cell-based OcclusionChip enables detection of sickle hemoglobin (HbS)-related RBC abnormalities in SCT and SCD, particularly when the HbS level is low. We conclude that the OcclusionChip is complementary to the population based ektacytometry assays, and providing additional sensitivity and capacity to detect modest abnormalities in red cell function or small populations of abnormal red cells.

Antithrombin-III mitigates thrombin-mediated endothelial cell contraction and sickle red blood cell adhesion in microscale flow

Individuals with sickle cell disease (SCD) have persistently elevated thrombin generation that results in a state of systemic hypercoagulability. Antithrombin‐III (ATIII), an endogenous serine protease inhibitor, inhibits several enzymes in the coagulation cascade, including thrombin. Here, we utilize a biomimetic microfluidic device to model the morphology and adhesive properties of endothelial cells (ECs) activated by thrombin and examine the efficacy of ATIII in mitigating the adhesion of SCD patient‐derived red blood cells (RBCs) and EC retraction. Microfluidic devices were fabricated, seeded with ECs, and incubated under physiological shear stress. Cells were then activated with thrombin with or without an ATIII pretreatment. Blood samples from subjects with normal haemoglobin (HbAA) and subjects with homozygous SCD (HbSS) were used to examine RBC adhesion to ECs. Endothelial cell surface adhesion molecule expression and confluency in response to thrombin and ATIII treatments were also evaluated. We found that ATIII pretreatment of ECs reduced HbSS RBC adhesion to thrombin‐activated endothelium. Furthermore, ATIII mitigated cellular contraction and reduced surface expression of von Willebrand factor and vascular cell adhesion molecule‐1 (VCAM‐1) mediated by thrombin. Our findings suggest that, by attenuating thrombin‐mediated EC damage and RBC adhesion to endothelium, ATIII may alleviate the thromboinflammatory manifestations of SCD.

Anticipatory Burden in Adult-Child Caregivers: A Concept Analysis

This study aims to analyze the concept of anticipatory burden in adult-child caregivers. A systematic literature review was performed using four databases, Pubmed, CINAHL, PsycINFO and Medline, with the keywords of “anticipatory burden” and “anticipated burden”. Simplified Wilson’s classic concept analysis modified by Walker and Avant was employed to identify the attributes, antecedents and consequences of anticipatory burden in the adult-child caregivers. Eighteen articles were analyzed. Attributes of anticipatory burden in adult-child caregivers were found to be: (1) subjective burden, (2) anticipation, (3) overestimation, (4) inability, and (5) family relationship. Antecedents were identified as: (1) potential care recipients, (2) caregiving willingness, and (3) a lack of resources. Consequences included: (1) prediction of caregiving willingness, (2) impacts on caregivers’ health, (3) intervention promotion, and (4) behavioral changes. As the adult-child caregiver is one of the main types of family caregivers for the fast-growing aging population, it is important to understand the attributes, antecedents, and consequences of their anticipatory burden. Based on the results of this study, resources such as intervention, policy, and counseling services are recommended to help adult-child caregivers lower their anticipatory burden and get better prepared for providing family care.

[Application of face scanning in implant-supported restoration treatment of dentition defect]

In recent years, the increasingly mature oral digital technology has opened a new era of implant treatment. Before implant treatment, digital information is collected from various aspects and virtual patients are constructed based on three-dimensional (3D) scanning technology, and this greatly optimizes the preoperative virtual tooth arrangement, esthetic design and implant treatment plan, and brings great clinical convenience to patients and doctors. In this review, the application and new progress of facial 3D scanning technology in the field of implantology will be described, and the opportunities and challenges brought by digitalization technology to clinicians will be deeply discussed, in order to provide a reference for implantologists to fully understand the application of digitalization in the field of implantology.

Point-of-care microchip electrophoresis for integrated anemia and hemoglobin variant testing

Anemia affects over 25% of the world's population with the heaviest burden borne by women and children. Genetic hemoglobin (Hb) variants, such as sickle cell disease, are among the major causes of anemia. Anemia and Hb variant are pathologically interrelated and have an overlapping geographical distribution. We present the first point-of-care (POC) platform to perform both anemia detection and Hb variant identification, using a single paper-based electrophoresis test. Feasibility of this new integrated diagnostic approach is demonstrated via testing individuals with anemia and/or sickle cell disease. Hemoglobin level determination is performed by an artificial neural network (ANN) based machine learning algorithm, which achieves a mean absolute error of 0.55 g dL^-1 and a bias of -0.10 g dL^-1 against the gold standard (95% limits of agreement: 1.5 g dL^-1) from Bland-Altman analysis on the test set. Resultant anemia detection is achieved with 100% sensitivity and 92.3% specificity. With the same tests, subjects with sickle cell disease were identified with 100% sensitivity and specificity. Overall, the presented platform enabled, for the first time, integrated anemia detection and hemoglobin variant identification using a single point-of-care test.

Emerging point-of-care technologies for anemia detection

Anemia, characterized by low blood hemoglobin level, affects about 25% of the world's population with the heaviest burden borne by women and children. Anemia leads to impaired cognitive development in children, as well as high morbidity and early mortality among sufferers. Anemia can be caused by nutritional deficiencies, oncologic treatments and diseases, and infections such as malaria, as well as inherited hemoglobin or red cell disorders. Effective treatments are available for anemia upon early detection and the treatment method is highly dependent on the cause of anemia. There is a need for point-of-care (POC) screening, early diagnosis, and monitoring of anemia, which is currently not widely accessible due to technical challenges and cost, especially in low- and middle-income countries where anemia is most prevalent. This review first introduces the evolution of anemia detection methods followed by their implementation in current commercially available POC anemia diagnostic devices. Then, emerging POC anemia detection technologies leveraging new methods are reviewed. Finally, we highlight the future trends of integrating anemia detection with the diagnosis of relevant underlying disorders to accurately identify specific root causes and to facilitate personalized treatment and care.

Blood Flow Velocimetry in a Microchannel During Coagulation Using Particle Image Velocimetry and Wavelet-Based Optical Flow Velocimetry

This article describes novel measurements of the velocity of whole blood flow in a microchannel during coagulation. The blood is imaged volumetrically using a simple optical setup involving a white light source and a microscope camera. The images are processed using particle image velocimetry (PIV) and wavelet-based optical flow velocimetry (wOFV), both of which use images of individual blood cells as flow tracers. Measurements of several clinically relevant parameters such as the clotting time, decay rate, and blockage ratio are computed. The high-resolution wOFV results yield highly detailed information regarding thrombus formation and corresponding flow evolution that is the first of its kind.

Microfluidic electrical impedance assessment of red blood cell-mediated microvascular occlusion

Alterations in the deformability of red blood cells (RBCs), occurring in hemolytic blood disorders such as sickle cell disease (SCD), contribute to vaso-occlusion and disease pathophysiology. There are few functional in vitro assays for standardized assessment of RBC-mediated microvascular occlusion. Here, we present the design, fabrication, and clinical testing of the Microfluidic Impedance Red Cell Assay (MIRCA) with embedded capillary network-based micropillar arrays and integrated electrical impedance measurement electrodes to address this need. The micropillar arrays consist of microcapillaries ranging from 12 μm to 3 μm, with each array paired with two sputtered gold electrodes to measure the impedance change of the array before and after sample perfusion through the microfluidic device. We define RBC occlusion index (ROI) and RBC electrical impedance index (REI), which represent the cumulative percentage occlusion and cumulative percentage impedance change, respectively. We demonstrate the promise of MIRCA in two common red cell disorders, SCD and hereditary spherocytosis. We show that the electrical impedance measurement reflects the microvascular occlusion, where REI significantly correlates with ROI that is obtained via high-resolution microscopy imaging of the microcapillary arrays. Further, we show that RBC-mediated microvascular occlusion, represented by ROI and REI, associates with clinical treatment outcomes and correlates with in vivo hemolytic biomarkers, lactate dehydrogenase (LDH) level and absolute reticulocyte count (ARC) in SCD. Impedance measurement obviates the need for high-resolution imaging, enabling future translation of this technology for widespread access, portable and point-of-care use. Our findings suggest that the presented microfluidic design and the integrated electrical impedance measurement provide a reproducible functional test for standardized assessment of RBC-mediated microvascular occlusion. MIRCA and the newly defined REI may serve as an in vitro therapeutic efficacy benchmark for assessing the clinical outcome of emerging RBC-modifying targeted and curative therapies.

Standardized microfluidic assessment of red blood cell-mediated microcapillary occlusion: Association with clinical phenotype and hydroxyurea responsiveness in sickle cell disease

OBJECTIVES

We present a standardized in vitro microfluidic assay and Occlusion Index (OI) for the assessment of red blood cell (RBC)-mediated microcapillary occlusion and its clinical associations in sickle cell disease (SCD).

METHODS

Red blood cell mediated microcapillary occlusion represented by OI and its clinical associations were assessed for seven subjects with hemoglobin-SC disease (HbSC), 18 subjects with homozygous SCD (HbSS), and five control individuals (HbAA).

RESULTS

We identified two sub-populations with HbSS based on the OI distribution. HbSS subjects with relatively higher OIs had significantly lower hemoglobin levels, lower fetal hemoglobin (HbF) levels, and lower mean corpuscular volume (MCV), but significantly higher serum lactate dehydrogenase levels and absolute reticulocyte counts, compared to subjects with HbSS and lower OIs. HbSS subjects who had relatively higher OIs were more likely to have had a concomitant diagnosis of intrapulmonary shunting (IPS). Further, lower OI associated with hydroxyurea (HU) responsiveness in subjects with HbSS, as evidenced by significantly elevated HbF levels and MCV.

CONCLUSIONS

We demonstrated that RBC-mediated microcapillary occlusion and OI associated with subject clinical phenotype and HU responsiveness in SCD. The presented standardized microfluidic assay may be useful for evaluating clinical phenotype and assessing therapeutic outcomes in SCD, including emerging targeted and curative treatments that aim to improve RBC deformability and microcirculatory health.

Neural peptide promotes the angiogenesis and osteogenesis around oral implants

Generally, impaired bones heal by bone repair and bone regeneration. These two processes are necessary during the healing period of dental implant. Vasculature plays a crucial role in bone healing because bones are highly vascularized tissue. Osteogenesis and angiogenesis are highly coupled processes and can be regulated by Hippo-YAP signaling pathway. Recent studies have demonstrated Hippo-YAP pathway may be regulated by alpha calcitonin gene-related peptide. However, the regulatory effects of αCGRP-YAP pathway on angiogenesis and osteogenesis during bone healing around implants remain unclear. Four groups of mice were established: KO Group: αCGRP ^-/- mice; KO + αCGRP group: αCGRP ^-/- mice with αCGRP overexpressing lentiviral transfection; KO + YAP group: αCGRP ^-/- mice with YAP overexpressing lentiviral transfection; WT group: wildtype mice. After 14 or 28 days, animals were sacrificed and tested. Results showed αCGRP deficiency hampered osteogenesis and angiogenesis. In addition, the impaired bone healing can be rescued by overexpressing αCGRP and YAP in αCGRP ^-/- mice. In-vivo results indicate αCGRP-YAP pathway promotes angiogenesis and osteogenesis in bone healing, especially at the early stage. Taken together, present study demonstrated αCGRP up-regulate the expression of YAP, and down-stream genes to promote the osteogenesis and angiogenesis around the implants.

Whole blood viscosity and red blood cell adhesion: Potential biomarkers for targeted and curative therapies in sickle cell disease

Sickle cell disease (SCD) is a recessive genetic blood disorder exhibiting abnormal blood rheology. Polymerization of sickle hemoglobin, due to a point mutation in the β‐globin gene of hemoglobin, results in aberrantly adhesive and stiff red blood cells (RBCs). Hemolysis, abnormal RBC adhesion, and abnormal blood rheology together impair endothelial health in people with SCD, which leads to cumulative systemic complications. Here, we describe a microfluidic assay combined with a micro particle image velocimetry technique for the integrated in vitro assessment of whole blood viscosity (WBV) and RBC adhesion. We examined WBV and RBC adhesion to laminin (LN) in microscale flow in whole blood samples from 53 individuals with no hemoglobinopathies (HbAA, N = 10), hemoglobin SC disease (HbSC, N = 14), or homozygous SCD (HbSS, N = 29) with mean WBV of 4.50 cP, 4.08 cP, and 3.73 cP, respectively. We found that WBV correlated with RBC count and hematocrit in subjects with HbSC or HbSS. There was a significant inverse association between WBV and RBC adhesion under both normoxic and physiologically hypoxic (SpO₂ of 83%) tests, in which lower WBV associated with higher RBC adhesion to LN in subjects with HbSS. Low WBV has been found by others to associate with endothelial activation. Altered WBV and abnormal RBC adhesion may synergistically contribute to the endothelial damage and cumulative pathophysiology of SCD. These findings suggest that WBV and RBC adhesion may serve as clinically relevant biomarkers and endpoints in assessing emerging targeted and curative therapies in SCD.

Inhibition of Band 3 tyrosine phosphorylation: a new mechanism for treatment of sickle cell disease

Many hypotheses have been proposed to explain how a glutamate to valine substitution in sickle haemoglobin (HbS) can cause sickle cell disease (SCD). We propose and document a new mechanism in which elevated tyrosine phosphorylation of Band 3 initiates sequelae that cause vaso-occlusion and the symptoms of SCD. In this mechanism, denaturation of HbS and release of heme generate intracellular oxidants which cause inhibition of erythrocyte tyrosine phosphatases, thus permitting constitutive tyrosine phosphorylation of Band 3. This phosphorylation in turn induces dissociation of the spectrin-actin cytoskeleton from the membrane, leading to membrane weakening, discharge of membrane-derived microparticles (which initiate the coagulation cascade) and release of cell-free HbS (which consumes nitric oxide) and activates the endothelium to express adhesion receptors). These processes promote vaso-occlusive events which cause SCD. We further show that inhibitors of Syk tyrosine kinase block Band 3 tyrosine phosphorylation, prevent release of cell-free Hb, inhibit discharge of membrane-derived microparticles, increase sickle cell deformability, reduce sickle cell adhesion to human endothelial cells, and enhance sickle cell flow through microcapillaries. In view of reports that imatinib (a Syk inhibitor) successfully treats symptoms of sickle cell disease, we suggest that Syk tyrosine kinase inhibitors warrant repurposing as potential treatments for SCD.

Microfluidic assessment of red blood cell mediated microvascular occlusion

Abnormal red blood cell (RBC) deformability contributes to hemolysis, thrombophilia, inflammation, and microvascular occlusion in various circulatory diseases. A quantitative and objective assessment of microvascular occlusion mediated by RBCs with abnormal deformability would provide valuable insights into disease pathogenesis and therapeutic strategies. To that end, we present a new functional microfluidic assay, OcclusionChip, which mimics two key architectural features of the capillary bed in the circulatory system. First, the embedded micropillar arrays within the microchannel form gradient microcapillaries, from 20 μm down to 4 μm, which mimic microcapillary networks. These precisely engineered microcapillaries retain RBCs with impaired deformability, such that stiffer RBCs occlude the wider upstream microcapillaries, while less stiff RBCs occlude the finer downstream microcapillaries. Second, the micropillar arrays are coupled with two side passageways, which mimic the arteriovenous anastomoses that act as shunts in the capillary bed. These side microfluidic anastomoses prevent microchannel blockage, and enable versatility and testing of clinical blood samples at near-physiologic hematocrit levels. Further, we define a new generalizable parameter, Occlusion Index (OI), which is an indicative index of RBC deformability and the associated microcapillary occlusion. We demonstrate the promise of OcclusionChip in diverse pathophysiological scenarios that result in impaired RBC deformability, including mercury toxin, storage lesion, end-stage renal disease, malaria, and sickle cell disease (SCD). Hydroxyurea therapy improves RBC deformability and increases fetal hemoglobin (HbF%) in some, but not all, treated patients with SCD. HbF% greater than 8.6% has been shown to improve clinical outcomes in SCD. We show that OI associates with HbF% in 16 subjects with SCD. Subjects with higher HbF levels (HbF > 8.6%) displayed significantly lower OI (0.88% ± 0.10%, N = 6) compared with those with lower HbF levels (HbF ≤ 8.6%) who displayed greater OI (3.18% ± 0.34%, N = 10, p < 0.001). Moreover, hypoxic OcclusionChip assay revealed a significant correlation between hypoxic OI and subject-specific sickle hemoglobin (HbS) level in SCD. OcclusionChip enables versatile in vitro assessment of microvascular occlusion mediated by RBCs in a wide range of clinical conditions. OI may serve as a new parameter to evaluate the efficacy of treatments improving RBC deformability, including hemoglobin modifying drugs, anti-sickling agents, and genetic therapies.

Leukocyte adhesion to P-selectin and the inhibitory role of Crizanlizumab in sickle cell disease: A standardized microfluidic assessment

Upregulated expression of P-selectin on activated endothelium and platelets significantly contributes to the initiation and progression of vaso-occlusive crises (VOC), a major cause of morbidity in sickle cell disease (SCD). Crizanlizumab (ADAKVEO®), a humanized monoclonal antibody against P-selectin, primarily inhibits the interaction between leukocytes and P-selectin, and has been shown to decrease the frequency of VOCs in clinical trials. However, the lack of reliable in vitro assays that objectively measure leukocyte adhesion to P-selectin remains a critical barrier to evaluating and improving the therapeutic treatment in SCD. Here, we present a standardized microfluidic BioChip whole blood adhesion assay to assess leukocyte adhesion to P-selectin under physiologic flow conditions. Our results demonstrated heterogeneous adhesion by leukocytes to immobilized P-selectin, and dose-dependent inhibition of this adhesion following pre-exposure to Crizanlizumab. Importantly, treatment with Crizanlizumab following adhesion to P-selectin promoted detachment of rolling, but not of firmly adherent leukocytes. Taken together, our results suggest that the microfluidic BioChip system is a promising in vitro assay with which to screen patients, monitor treatment response, and guide current and emerging anti-adhesive therapies in SCD.

[Value of dual-energy CT-based volumetric iodine-uptake in the evaluation of chemotherapy efficacy in advanced gastric cancer]

Objective: To explore the value of dual-energy CT-based volumetric iodine-uptake (VIU) in the evaluation of chemotherapy efficacy in advanced gastric cancer. Methods: Inclusion criteria of subjects: (1) without previous systematic therapy; (2) with complete clinical information before and after chemotherapy; (3) without contraindications of chemotherapy. Exclusion criteria of subjects: (1) unfinished duration and times of chemotherapy; (2) unmeasurable primary lesions; (3) poor imaging quality or poor gastric filling. Clinical and image data of 52 patients with advanced gastric cancer who were diagnosed by pathology from gastroscopic biopsy, and needed chemotherapy evaluated by imaging and clinical information in the First Affiliated Hospital of Wenzhou Medical University from February 2017 to February 2018 were collected and analyzed. Of 52 patients, 38 were male and 14 were female with the median age of 65 (31-88) years old. All the patients underwent a dual-energy, dual phase-enhanced CT scanning before chemotherapy and after the third chemotherapy session. The parameters of the lesions measured before and after chemotherapy in portal vein phase were as follows: the maximum diameter (the largest diameter among those measured in the cross-sectional, coronal, and sagittal planes), average CT value (the regions of interest were manually pinpointed under cross-sectional planes with largest diameter of the tumor, which did not include regions less than 2 mm to the edge of the tumor) and VIU (lesion volume × iodine concentration). The change rates of maximum lesion diameter, average CT value and VIU before and after chemotherapy were calculated [(post-chemotherapy parameters-pre-chemotherapy parameters)/ pre-chemotherapy parameters]. The efficacy of chemotherapy was evaluated by RECIST 1.1 (the change of maximum tumor diameter after chemotherapy), Choi (the change of average CT value after chemotherapy) and VIU (the change of VIU after chemotherapy), respectively, which was categorized by complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). Patients with CR, PR, and SD were assigned to the effective group, while those with PD were classified as the ineffective group. Paired t - test or Wilcoxon signed ranks test was used to compare the changes of parameters before and after chemotherapy, whereas Spearman correlation analysis and Kappa test were used for the correlation analysis and the consistency test between the three evaluation criteria (Kappa≥0.75 indicated good consistency). Results: After chemotherapy, the average CT value [(74.01±16.75) HU vs. (81.06±15.87) HU, t=2.202, P=0.030] and median VIU (668.53×10(2) μg vs. 272.52×10(2) μg, Z=4.761, P<0.001) decreased significantly, while the difference of the maximum diameter was not statistically significant [(66.71±34.49) mm vs. (78.45±35.62) mm, t=1.708, P=0.091]. The median change rate of VIU (-53.33%) was greater than that of CT values (-5.75%) with significant difference (Z=-5.408, P<0.001). According to the RECIST 1.1 criteria, 47 patients (90.4%, including 19 with PR and 28 with SD) were effective and 5 patients (9.6%) were ineffective. According to the Choi criteria, 45 patients (86.5%, including 37 with PR and 8 with SD) were effective and 7 patients (13.5%) were ineffective. According to the VIU criteria, 46 patients (88.5%, including 41 with PR and 5 with SD) were effective and 6 patients (11.5%) were ineffective. Efficacy comparison among these three criteria showed no significant difference (χ(2)=0.377, P=0.828). As compared to RECIST 1.1 evaluation, the proportion of PR evaluated by Choi and VIU was significantly higher (χ(2)=16.861, P<0.001), whereas the proportion of SD was significantly lower (χ(2)=24.089, P<0.001). There was no significant difference in the proportions of PR and SD between VIU and Choi criteria (χ(2)=0.887, P=0.346). Consistency and correlation analysis showed that the VIU and Choi evaluation criteria presented the highest consistency and correlation (Kappa=0.912, P<0.001; r=0.916, P<0.001). Conclusion: VIU is a feasible parameter for the evaluation of chemotherapy efficacy in advanced gastric cancer, and may be more sensitive than the evaluation criteria based on maximum diameter or change of CT value in the tumor.

Apical U-shape splitting technique for undercut areas of the anterior alveolar ridge: a prospective non-randomized controlled study

The aim of this study was to investigate a novel apical U-shape splitting technique for horizontal bone augmentation in undercut areas and to compare its efficacy with that of guided bone regeneration (GBR). This was a prospective non-randomized controlled clinical trial. A total of 36 patients, who presented with a labial undercut that was not able to house a normally inclined implant, underwent the new technique or GBR. Radiographic and clinical data were obtained preoperatively, immediately after surgery, and 12 months after surgery. Pairwise comparisons of changes in ridge width gain, marginal bone loss, and pink aesthetic score were performed; correlations with pristine ridge morphology were investigated. The results showed similar marginal bone loss in the two groups. The overall ridge width gains in the new technique group (2.56±1.92mm) and GBR group (0.73±1.21mm) differed significantly (P<0.05). The pink aesthetic score was higher for the new technique group (11.75±1.22) than for the GBR group (9.25±1.86) (P<0.01). The morphology of the concavity had different impacts on regeneration in the two groups. The apical U-shape splitting technique, as a safe and effective alternative to GBR, provided a significant increase in bone volume gain where labial fenestration was inevitable during implant placement.

Significant Enhancement of the Adhesion between Metal Films and Polymer Substrates by UV-Ozone Surface Modification in Nanoscale

Polymer metallization is extensively used in a variety of micro- and nanosystem technologies. However, the deposited metal film exhibits poor adhesion to polymer substrates, which may cause difficulties in many applications. In this work, ultraviolet (UV)-ozone surface modification is for the first time put forward to enhance the adhesion between metal films and polymer substrates. The adhesion of sputtered Cu films on UV-ozone modified poly(methyl methacrylate) (PMMA) substrates is enhanced by a factor of 6, and that of Au films is improved by a factor of 10. Moreover, metal films on the modified PMMA substrates can withstand a long-time liquid immersion. To understand the mechanism for the adhesion enhancement, the surface modification is studied with contact angle measurements, attenuated total reflection Fourier-transform infrared spectrometry (ATR-FTIR) and atomic force microscopy (AFM). Detailed characterization results indicate that the significant adhesion enhancement is attributed to the increases of both the surface wettability by generating some polar functional groups and the roughness of the surface in nanoscale. To demonstrate this novel polymer metallization method, a 6-in. PMMA chip with arrays of three-electrode electrochemical microsensors is designed and fabricated, and the microsensor exhibits excellent reproducibility, uniformity, and long-term stability.

A palatal roll envelope technique for peri-implant mucosa reconstruction: a prospective case series study

The aim of this study was to evaluate peri-implant soft tissue changes after performing a palatal roll envelope technique. Twelve patients, presenting a labial flat or concave profile before second-stage surgery, underwent soft tissue augmentation using the palatal roll envelope technique with papilla reservation design. The convex profile on the facial aspect, Jemt papilla index, facial mucosal level, marginal bone level, proximal bone levels of the adjacent teeth, and surgical/prosthetic complications were evaluated before surgery as the baseline, and then reevaluated at 1 week, 3 months, and 6 months after surgery. Data were analyzed using the Friedman test and Wilcoxon signed-rank test. Results indicated that the convex profile and the average papilla index score were improved, while the facial mucosal level was adjusted to a level similar to that of the contralateral tooth at 3 months and then remained stable for the follow-up visit. With the limitations identified in this report, the palatal roll envelope technique can be considered an alternative method to augment the soft tissue during second-stage surgery. This technique obviates the need for another surgical site and papillae area, and also reduces the risks of graft shrinkage and scarring on the labial site.

Knockdown of AXL receptor tyrosine kinase in osteosarcoma cells leads to decreased proliferation and increased apoptosis

Dysregulation of the Axl receptor tyrosine kinase (RTK) has been implicated in the development and progression of a variety of malignancies. Axl is known to activate strong anti-apoptotic signaling pathways that promote oncogenesis. However, the role of Axl plays in osteosarcoma (OS) remains elusive. The present study aimed to investigate the clinical significance and function of Axl in human OS. Forty cases of OS and corresponding adjacent non-cancerous tissues (ANCT) were collected. The expression of Axl was assessed using immunohistochemical assay through tissue microarray procedure. A loss-of-function experiment was performed to investigate the effects of small hairpin RNA (shRNA)-mediated knockdown of Axl on the expression of p-AKT, poly ADP-ribose polymerase (PARP) and Ki-67, the proliferative activities, indicated by MTT assay, and the apoptotic index in OS MG-63 cells. As a result, the expression of Axl was found in OS tissues with higher strong reactivity rate, compared with the ANCT (75.0 percent vs 20.0 percent, P=0.000), but it did not associate with the age, gender, tumor size, TNM staging and distant metastases (each Pgreater than0.05). Furthermore, knockdown of Axl inhibited the proliferative activities and induced apoptosis in MG-63 cells with decreased expression of p-AKT, and Ki-67 and increased expression of PARP. In conclusion, our findings suggest that Axl is highly expressed in most of the OS tissues compared with the ANCT, and knockdown of Axl inhibits proliferation and induces apoptosis of OS cells possibly through downregulation of the AKT pathway, suggesting that our findings may provide new insights into the potential therapeutic target for cancer.

Defect modes in one-dimensional granular crystals

We study the vibrational spectra of one-dimensional statically compressed granular crystals (arrays of elastic particles in contact) containing light-mass defects. We focus on the prototypical settings of one or two spherical defects (particles of smaller radii) interspersed in a chain of larger uniform spherical particles. We present a systematic measurement, using continuous noise, of the near-linear frequency spectrum within the spatial vicinity of the defect(s). Using this technique, we identify the frequencies of the localized defect modes as a function of the defect size and the position of the defects relative to each other. We also compare the experimentally determined frequencies with those obtained by numerical eigenanalysis and by analytical expressions based on few-site considerations. These approximate analytical expressions, based on normal-mode analysis, are found to be in excellent agreement with numerics for a wide range of mass ratios. We also observe that the experimentally measured frequencies of the localized defect modes are uniformly upshifted, compared to the numerically and theoretically predicted values.

CAPC expression correlates with breast tumor progression and invasion

Abstract #4044

Background: Recent studies identified a uncharacterized gene that encodes a molecule named as cytokeratin-associated protein in cancer (CAPC). RT-PCR analysis detected significant elevation of CAPC mRNA in 26 of 33 human breast cancers. Our current study attempted to elucidate CAPC protein expression profile in human breast tissues, to assess: [1] if CAPC expression is associated with tumor progression and invasion, and [2] if CAPC is co-expressed with BP1 and c-erbB2, two known invasiveness and aggressiveness-related proteins.&#x2028; Materials and Methods: Consecutive sections were prepared from paraffin-embedded breast tissues from 100 female patients with breast tumors that harbored co-existing normal, hyperplastic, in situ, and invasive components. Sets of four adjacent sections from each case were subjected to immunohistochemistry for CAPC, BP1, c-erbB2, and Ki-67. The expression status of these molecules in different tissue components were statistically compared.&#x2028; Results: In normal breasts and hyperplastic or in situ breast lesions, CAPC positive cells were generally distributed as duct or acinar clusters with a distinct boundary with their CAPC negative counterparts. Under low magnification of H&E stained sections, these CAPC positive duct or acinar clusters were morphologically indistinguishable from their CAPC negative counterparts. Under high magnification, however, the myoepithelial cell layers of these CAPC positive clusters were focally disrupted, and the associated epithelial cells often showed malignancy-associated nuclear alterations. Both the number of CAPC positive cells and the intensity of CAPC immunostaining linearly increased with tumor progression and invasion. In invasive lesions, a vast majority of cancer cells in over 80% of the cases expressed high levels of CAPC. A majority of the normal, benign, and malignant tumors with high levels of CAPC showed substantially higher expression of BP1 and c-erbB2, along with a higher proliferation index, compared to their morphologically similar CAPC negative counterparts . In non-mitotic cells, CAPC was localized mainly in the cytoplasm. In malignant mitotic cells, high levels of CAPC expression were localized close to the cell membrane, forming a ring-like structure surrounding condensed chromosomes. In contrast, no distinct CAPC was detected in normal or hyperplastic mitotic cells.&#x2028; Discussion: These findings suggest CAPC might be a tumor specific marker that could be used for the development of diagnostic and/or therapeutic agents.&#x2028; Acknowledgment: Supported in part by grant BCTR0706983 from The Susan G. Komen Breast Cancer Foundation and grant 2006CB910505 from the Ministry of Chinese Science and Technology Department.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4044.

Maintenance of the epithelial barrier in a bronchial epithelial cell line is dependent on functional E-cadherin local to the tight junctions

Tight junctions (TJ) are essential components of polarized epithelia, and E-cadherin is important for their formation and maintenance. The bronchial epithelial cell line, 16HBE14o-expresses E- and P-cadherin, but not N-cadherin. E- and P-cadherin levels changed during culture, the former increasing after confluence, and the latter were markedly reduced. All detectable E-cadherin was bound to beta- and gamma-catenins. We investigated involvement of E-cadherin with epithelial integrity using an E-cadherin specific, function-blocking antibody, SHE78-7. Surprisingly, apical SHE78-7 exposure caused a prompt fall in transepithelial resistance (TER), while TER remained unchanged for 8 hrs after basal exposure then dropped. SHE78-7 exposure increased epithelial permeability to mannitol, inulin, and 9.5 kDa and 77 kDa dextrans and caused fragmentation and loss of the tight junction protein, ZO-1, from the cell borders in some areas. Ultrastructural studies showed that all junctional intercellular contact was lost in the center of SHE78-7 induced lesions. Near the lesion periphery, epithelial structure was maintained, but TJs were dysfunctional as shown by ruthenium red penetration. Analysis of epithelial penetration by SHE78-7 revealed discrete, local defects in the apical barrier at the top of some cell hills that permitted rapid access of the antibody to E-cadherin near the apical surface. In contrast, after basal exposure, antibody initially engaged with E-cadherin nearer the basal surface and only accessed apical E-cadherin later. Taken together with the TER measurements, these data suggest compartmentalization of E-cadherin function within 16HBE14o-cells, with only the apical E-cadherin adjacent to the tight junctions contributing to the function of the latter.

Allelic losses at 3p and 11p are detected in both epithelial and stromal components of cervical small-cell neuroendocrine carcinoma

Microdissected epithelial and stromal cells from 15 cervical small-cell carcinoma patients and 9 healthy control subjects were assessed for loss of heterozygosity with polymorphic DNA markers at chromosomes 3p and 11p. Among malignant lesions assessed with 7 markers at 3p, 21 allelic losses were detected from 193 informative samples. Of losses, 20 were in epithelial and 1 was in normal-appearing stromal cells. Among losses in epithelial cells, 16 were from 44 samples informative for 3 markers within 3p21.2-p14.2 (0.36 loss/sample), whereas only 4 were from 54 samples informative for 4 markers outside the region (0.09 loss/sample), suggesting a "hot spot" of genetic alterations within 3p21.2-p14.2. Among malignant lesions assessed with 2 markers within 11p14-p12, 15 losses were seen in 52 informative samples. Of losses, 10 were in epithelial and 5 were in normal-appearing stromal cells. Of 10 epithelial samples showing losses within 11p14-p12, 8 also displayed losses within 3p21.2-p14.2, suggesting a concurrent involvement of these loci in tumor development or progression. The five losses in stromal cells were in four cases that showed no loss in epithelial cells with same markers, suggesting that stromal cells might play initiative roles in tumor development.

Loss of epithelial integrity resulting from E-cadherin dysfunction predisposes airway epithelial cells to adenoviral infection

Epithelial intercellular adhesion is fundamental to the formation of the airway epithelial protective barrier. In this respect, cadherins are important because these adhesion molecules regulate formation and maintenance of epithelial intercellular junctions. To study the importance of airway epithelial integrity in determining susceptibility to virus infection, we used a replication-incompetent adenovirus, RAd35, and an E-cadherin specific function-blocking antibody, SHE78-7, to disrupt intercellular contacts in human bronchial epithelial cell line 16HBE14o- and primary bronchial epithelial cells. After exposure of 16HBE14o- cell cultures to SHE78-7, disruption of the transepithelial permeability barrier was indicated by a loss of transepithelial electrical resistance and an associated increase of mannitol, inulin, and dextran paracellular flux. Subsequent exposure of SHE78-7-treated cell cultures to RAd35 showed a remarkable increase in adenoviral infection as assessed by beta-galactosidase reporter gene expression. In cultures exposed to SHE78-7, disruption of E-cadherin function resulted in infection equivalent to that in control cultures using 16-fold lower viral titers. These studies show that manipulation of E-cadherin function provides a specific means of altering epithelial integrity that in turn determines resistance of airway epithelia to adenoviral infection.

Five useful approaches for generating more valid gel images of loss of heterozygosity and clonality analysis with an automated 377 DNA sequencer

The recently introduced fluorescence-based gene scan system for assessment of loss of heterozygosity (LOH) and clonality with an automated DNA sequencer has several advantages over the traditional method. However, the production of gel images with this system is subjected to more technical challenges, including the interference of autofluorescence, weaker and less consistent signals that result from the restricted well size and difficulties in sample loading. To minimize the impact of these technical difficulties, several unique strategies were used, including the following: elimination of fabrics or paper towels in the cleaning of gel plates and containers; use of a modified loading buffer; use of more concentrated gels; use of an innovative apparatus to clean gel wells before and after the prerun; and covering the black printer cartridge with a sheet of scotch tape. With these strategies, the authors have been able to consistently obtain gel images that can be presented as either densitometric graphs or as band patterns for direct visual assessment.

Loss of heterozygosity is detected at chromosomes 1p35-36 (NB), 3p25 (VHL), 16p13 (TSC2/PKD1), and 17p13 (TP53) in microdissected apocrine carcinomas of the breast

INTRODUCTION

Apocrine carcinomas of the breast are an unusual special category of predominantly AR+, ER-, and PR- breast cancer, characterized by cells with abundant, eosinophilic cytoplasm and nuclei with often prominent nucleoli. To further investigate these lesions, loss of heterozygosity (LOH) was evaluated at multiple chromosomal loci, including loci frequently mutated in breast cancer.

MATERIALS AND METHODS

Twenty-five intraductal apocrine carcinomas, 11 invasive apocrine carcinomas, and six apocrine hyperplasias were retrieved from the files of the Armed Forces Institute of Pathology (Washington, DC) and Fairfax Hospital (Fairfax, VA). Cells from lesional as well as normal tissues were microdissected. LOH was performed at a number of chromosomal loci, including loci commonly altered in breast cancer: 1p35-36 (NB), 3p25.5 (VHL), 8p12 (D8S136), 9p21 (p16), 11p13 (D11S904), 11q13 (INT-2 and PYGM), 16p13.3 (TSC2/PKD1 gene region), 17p13 (TP53), 17q13 (NM23), and 22q12 (D22S683).

RESULTS

Among informative in situ and invasive apocrine carcinomas, LOH was present in 33% of 15 cases for 17p13 (TP53), as well as 36% of 14 cases for 3p25 (VHL), 30% of 10 cases for 1p35-36 (NB), and 27% of 11 cases for 16p13.3 (TSC2/PKD1). A higher frequency of LOH was noted among invasive apocrine carcinomas (30 to 50%) compared with in situ apocrine carcinomas (23 to 33%) at these loci. LOH was present simultaneously for TP53 and either VHL or NB in five cases. Infrequent (< or =12%) or absent LOH was detected at the remaining loci, including several loci commonly mutated in breast cancer (i.e., INT2, PYGM, and NM23). LOH was not detected in any of the six apocrine hyperplasias.

CONCLUSION

An intermediate frequency of allelic loss was detected at multiple tumor suppressor gene loci, including 17p13 (TP53), as well as 1p35-336 (NB), 3p25 (VHL), and 16p13 (PKD1/ TSC2), in apocrine carcinomas of the breast, with a higher overall frequency of LOH noted among invasive tumors compared with in situ tumors. Aside from LOH at p53, LOH was infrequent or absent at several other loci commonly mutated in breast cancer. This preliminary molecular evidence supports immunohistochemical data that apocrine carcinomas of the breast may possess unique mechanisms of carcinogenesis, compared with ordinary ductal carcinomas. However, further study is needed to support this assertion and to determine if the LOH detected is truly etiologic or if it is the result of genetic progression.

Picumeterol: dissociation of improvement in lung function and reduction of airways hyperresponsiveness in asthmatics

AIMS

The new potent and selective beta 2-adrenoceptor agonist, GR 114297A (picumeterol) is the R-enantiomer of the racemic form, GR 63411B. Picumeterol has been shown to produce long-lasting relaxation of airways smooth muscle both in vitro and in vivo. We assessed the intrinsic activity of picumeterol by increasing intracellular levels of c-AMP and compared this with isoprenaline and salbutamol.

METHODS

In human atopic asthmatics, we have investigated the duration of action and efficacy of picumeterol and GR 63411B with regard to improvement in resting lung function (i.e. FEV1) and airways responsiveness (i.e. PC20) to methacholine (MCh). The study design consists of two clinical parts each for one drug. Different asthmatics participated in the two studies, seven in the first part and eight in the second part. In human bronchial smooth muscle cells in vitro, we have investigated the intrinsic activity of picumeterol in increasing intracellular levels of cyclic AMP and compared it with isoprenaline and salbutamol.

RESULTS

In vivo, both drugs caused bronchodilatation with similar potency, but, their effects were short-lasting. Despite their bronchodilator activity, neither drug improved PC20, when compared with placebo. In vitro, picumeterol was found have intrinsic activity lower than the other beta 2-adrenoceptor agonists tested.

CONCLUSIONS

In the clinical studies, the bronchodilator potencies of picumeterol and GR 63411B were similar. However, both drugs were short-acting, which is at odds with their activity in vitro. Our data suggest that these compounds display dissociation between bronchodilator activity and protection against MCh-induced bronchoconstriction. These findings may be explained by low intrinsic activity and need further conformation.

Two nonradioactive assays for phosphotyrosine phosphatases with activity toward the insulin receptor

Two highly sensitive, nonradiolabeled assays for protein phosphotyrosine phosphatase (PTPase) have been developed. The first assay is based on the use of chemically synthesised phosphotyrosine-containing peptides that can be separated from the dephosphorylated peptide products by HPLC. In this assay, partially purified placental PTPase 1B dephosphorylated three dodecaphosphopeptides (corresponding to insulin receptor autophosphorylation sites at positions PY1146, PY1150, and PY1151) with approximately equal affinity (Km 1.3-2.5 microM), indicating that PTPase 1B shows no distinct preference for the site of dephosphorylation in these peptides. The second assay employs either a phosphopeptide or an autophosphorylated tyrosine kinase domain immobolized on microtiter plate wells. After reaction with PTPase, the remaining unconverted phosphosubstrate is detected in an ELISA using anti-phosphotyrosine antibodies. The latter assay was used to monitor PTPase activity during purification procedures and for characterizing PTPases. Modulation of PTPase activity by orthovanadate, heparin, Zn2+, and EDTA gave similar results in both assays. The immobilized autophosphorylated IR tyrosine kinase domain was a poor substrate for bovine liver alkaline phosphatase and seminal fluid acid phosphatase. The second assay also offers the potential for comparing PTPase activity toward several autophosphorylated tyrosine kinase domains, including those of the insulin, epidermal growth factor, and platelet-derived growth factor receptors.