Immune checkpoint inhibitor-related colitis in patients on immunotherapy for cancer

OBJECTIVES

Immune checkpoint inhibitors, a revolutionary class of cancer immunotherapy drugs, have transformed cancer treatment by bolstering antitumor immunity for various advanced-stage solid cancers. The US Food and Drug Administration has approved 7 immune checkpoint inhibitors that target 3 major immune checkpoint proteins: cytotoxic T-lymphocyte-associated protein 4, programmed cell death 1 protein, and programmed cell death 1 ligand 1. In addition to their remarkable efficacy, however, these inhibitors have been observed causing immune-related adverse events, particularly immune checkpoint inhibitor-related colitis, which often results in severe or life-threatening clinical issues.

METHODS

The diagnosis of immune checkpoint inhibitor-related colitis relies on incorporation of clinical evaluation as well as endoscopic and histopathologic examination, with exclusion of other potential etiologies.

RESULTS

The common histopathologic manifestations of immune checkpoint inhibitor-related colitis are acute active colitis, chronic active colitis, microscopic colitis (collagenous or lymphocytic), and ischemic colitis, with patterns overlapping. Notably, enterocyte apoptosis is a unique feature of immune checkpoint inhibitor toxicity. The proposed mechanisms for the pathogenesis of immune checkpoint inhibitor-related colitis are primarily associated with autoimmune-type dysregulation and gut microbiome alteration. This review summarizes the clinical and pathologic characteristics of immune checkpoint inhibitor-related colitis and elucidates its underlying pathogenic mechanisms.

CONCLUSIONS

Future successful management of this form of colitis relies on our comprehension of the intricate interplay between tumoral and systemic immune responses to immune checkpoint inhibitors and innovative approaches to modify these responses, along with specific immune cell populations, to preclude immune-related adverse events while achieving antitumor therapeutic outcomes.

Comparative oncology chemosensitivity assay for personalized medicine using low-coherence digital holography of dynamic light scattering from cancer biopsies

Nearly half of cancer patients who receive standard-of-care treatments fail to respond to their first-line chemotherapy, demonstrating the pressing need for improved methods to select personalized cancer therapies. Low-coherence digital holography has the potential to fill this need by performing dynamic contrast OCT on living cancer biopsies treated ex vivo with anti-cancer therapeutics. Fluctuation spectroscopy of dynamic light scattering under conditions of holographic phase stability captures ultra-low Doppler frequency shifts down to 10 mHz caused by light scattering from intracellular motions. In the comparative preclinical/clinical trials presented here, a two-species (human and canine) and two-cancer (esophageal carcinoma and B-cell lymphoma) analysis of spectral phenotypes identifies a set of drug response characteristics that span species and cancer type. Spatial heterogeneity across a centimeter-scale patient biopsy sample is assessed by measuring multiple millimeter-scale sub-samples. Improved predictive performance is achieved for chemoresistance profiling by identifying red-shifted sub-samples that may indicate impaired metabolism and removing them from the prediction analysis. These results show potential for using biodynamic imaging for personalized selection of cancer therapy.

Inverse problems in blood flow modeling: A review

Mathematical and computational modeling of the cardiovascular system is increasingly providing non-invasive alternatives to traditional invasive clinical procedures. Moreover, it has the potential for generating additional diagnostic markers. In blood flow computations, the personalization of spatially distributed (i.e., 3D) models is a key step which relies on the formulation and numerical solution of inverse problems using clinical data, typically medical images for measuring both anatomy and function of the vasculature. In the last years, the development and application of inverse methods has rapidly expanded most likely due to the increased availability of data in clinical centers and the growing interest of modelers and clinicians in collaborating. Therefore, this work aims to provide a wide and comparative overview of literature within the last decade. We review the current state of the art of inverse problems in blood flows, focusing on studies considering fully dimensional fluid and fluid-solid models. The relevant physical models and hemodynamic measurement techniques are introduced, followed by a survey of mathematical data assimilation approaches used to solve different kinds of inverse problems, namely state and parameter estimation. An exhaustive discussion of the literature of the last decade is presented, structured by types of problems, models and available data.

Validation of 4D Flow based relative pressure maps in aortic flows

While the clinical gold standard for pressure difference measurements is invasive catheterization, 4D Flow MRI is a promising tool for enabling a non-invasive quantification, by linking highly spatially resolved velocity measurements with pressure differences via the incompressible Navier-Stokes equations. In this work we provide a validation and comparison with phantom and clinical patient data of pressure difference maps estimators. We compare the classical Pressure Poisson Estimator (PPE) and the new Stokes Estimator (STE) against catheter pressure measurements under a variety of stenosis severities and flow intensities. Specifically, we use several 4D Flow data sets of realistic aortic phantoms with different anatomic and hemodynamic severities and two patients with aortic coarctation. The phantom data sets are enriched by subsampling to lower resolutions, modification of the segmentation and addition of synthetic noise, in order to study the sensitivity of the pressure difference estimators to these factors. Overall, the STE method yields more accurate results than the PPE method compared to catheterization data. The superiority of the STE becomes more evident at increasing Reynolds numbers with a better capacity of capturing pressure gradients in strongly convective flow regimes. The results indicate an improved robustness of the STE method with respect to variation in lumen segmentation. However, with heuristic removal of the wall-voxels, the PPE can reach a comparable accuracy for lower Reynolds' numbers.

South African Society of Anaesthesiologists Perioperative Patient Blood Management Guidelines 2020

Anaesthesiologists regularly request and administer blood components to their patients, a potentially life-saving intervention. All anaesthesiologists must be familiar with the indications and appropriate use of blood and blood components and their alternatives, but close liaison with haematologists and their local haematology blood sciences laboratory is encouraged. In the last decade, there have been considerable changes in approaches to optimal use of blood components, together with the use of alternative products, with a need to update previous guidelines and adapt them for anaesthesiologists working throughout the hospital system.

Abstract LB-264: Biodynamic chemotherapy selection in breast cancer patients

Purpose: Biodynamic signatures (temporal patterns of microscopic motion within a three-dimensional tumor explant) offer a phenomic biomarker that is highly predictive for therapeutic response. The purpose of this study is to evaluate predictive accuracy of a biodynamic drug response classifier in breast cancer patients receiving neoadjuvant chemotherapy (NAC). Methods: Consecutive breast cancer patients from 4 institutions were screened for enrollment in a prospective observational study (NCT03164863). Treatment-naïve needle biopsies were delivered to a central laboratory where biodynamic signatures were measured in living tumor fragments challenged by standard-of-care cytotoxins. Patients received NAC per institutional guidelines and were followed through surgical intervention. A four-point classifier was trained to predict pathologic complete response (CR) then prospectively validated. Results: Among patients completing neoadjuvant treatment and surgical intervention, 33% (24 of 72) achieved CR. The biodynamic classifier predicted CR with 96% sensitivity and 97% negative predictive value. Biodynamically “favored” (scoring ≥ 3) and “strongly favored” (scoring 4) regimens produced CR at rates of 56% (23 of 41) and 73% (19 of 26), respectively. Only 3% of patients (1 of 31) achieved CR from regimens scoring 1 or 2. Area under the receiver operating curve (AUC) was 87% (95% CI: 75% to 93%, p <.0001), with similar performance across all subtypes and therapy cohorts (range: 84% to 89%). Performance of the classifier on training and validation patients was statistically equivalent. Conclusion: Biodynamic scoring accurately predicts response in breast cancer patients receiving NAC and holds promise to substantially improve management of these patients.

Chemotherapy response distribution by biodynamic scoreBiodynamic ScoreNo ResponsePartial ResponseComplete ResponseTotal111 (58%)7 (37%)1 (5%)1922 (17%)10 (83%)0 (0%)1231 (7%)10 (67%)4 (27%)1540 (0%)7 (27%)19 (73%)26Totals14 (19%)34 (47%)24 (33%)72

Citation Format: Ran An, John Turek, David Nolte, David Loesch, Travis Morgan. Biodynamic chemotherapy selection in breast cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-264.

Biodynamic response prediction in breast cancer patients receiving neoadjuvant chemotherapy

e12643

Background: Biodynamic signatures (temporal patterns of microscopic motion within a three-dimensional tumor explant) offer a phenomic biomarker that is highly predictive for therapeutic response. The purpose of this study is to evaluate predictive accuracy of a biodynamic drug response classifier in breast cancer patients receiving neoadjuvant chemotherapy (NAC). Methods: Consecutive breast cancer patients from 4 institutions were screened for enrollment in a prospective observational study (NCT03164863). Treatment-naïve needle biopsies were delivered to a central laboratory where biodynamic signatures were measured in living tumor fragments challenged by standard-of-care cytotoxins. Patients received NAC per institutional guidelines and were followed through surgical intervention. A four-point classifier was trained to predict pathologic complete response (CR) then prospectively validated. Results: Among patients completing neoadjuvant treatment and surgical intervention, 33% (24 of 72) achieved CR. The biodynamic classifier predicted CR with 96% sensitivity and 97% negative predictive value. Biodynamically “favored” (scoring ≥ 3) and “strongly favored” (scoring 4) regimens produced CR at rates of 56% (23 of 41) and 73% (19 of 26), respectively. Only 3% of patients (1 of 31) achieved CR from regimens scoring 1 or 2. Area under the receiver operating curve (AUC) was 87% (95% CI: 75% to 93%, p < .0001), with similar performance across all subtypes and therapy cohorts (range: 84% to 89%). Performance of the classifier on training and validation patients was statistically equivalent. Conclusions: Biodynamic scoring accurately predicts response in breast cancer patients receiving NAC and holds promise to substantially improve management of these patients. [Table: see text]

Simulation of hypoxia PET-tracer uptake in tumours: Dependence of clinical uptake-values on transport parameters and arterial input function

Poor radiotherapy outcome is in many cases related to hypoxia, due to the increased radioresistance of hypoxic tumour cells. Positron emission tomography may be used to non-invasively assess the oxygenation status of the tumour using hypoxia-specific radiotracers. Quantification and interpretation of these images remains challenging, since radiotracer binding and oxygen tension are not uniquely related. Computer simulation is a useful tool to improve the understanding of tracer dynamics and its relation to clinical uptake parameters currently used to quantify hypoxia. In this study, a model for simulating oxygen and radiotracer distribution in tumours was implemented to analyse the impact of physiological transport parameters and of the arterial input function (AIF) on: oxygenation histograms, time-activity curves, tracer binding and clinical uptake-values (tissue-to-blood ratio, TBR, and a composed hypoxia-perfusion metric, FHP). Results were obtained for parallel and orthogonal vessel architectures and for vascular fractions (VFs) of 1% and 3%. The most sensitive parameters were the AIF and the maximum binding rate (K_max). TBR allowed discriminating VF for different AIF, and FHP for different K_max, but neither TBR nor FHP were unbiased in all cases. Biases may especially occur in the comparison of TBR- or FHP-values between different tumours, where the relation between measured and actual AIF may vary. Thus, these parameters represent only surrogates rather than absolute measurements of hypoxia in tumours.

1 Assessing the energy status of porcine embryos by means of biodynamic imaging

Assisted reproductive technologies are powerful tools for enhancing production in livestock or treating infertility in humans. Unfortunately, the success rate of the technologies is rather low. A major reason for the poor efficiency is the lack of methods to reliably assess the developmental potential of the embryos before transfer into recipients. Therefore, a noninvasive method to ensure the selection of only the best embryos for transfer would be highly desirable. Biodynamic imaging is a compelling new microscopy that uses intracellular Doppler spectroscopy to perform label-free, noninvasive optical measurements of cellular fitness. The aim of this study was to investigate whether biodynamic imaging can be used to assess the energy status of the embryos, which may be indicative of their viability. Porcine oocytes matured invitro were parthenogenetically activated by an electrical pulse and cultured for 2 days. The parthenotes were then divided into two groups, and approximately half of them were incubated for an additional 2 days in the presence of 20mM sodium azide. Sodium azide is an inhibitor of oxidative phosphorylation and is known to block ATP production. The rest of the embryos were cultured without sodium azide and used as a control to indicate normal ATP levels. At the end of the culture period embryos that reached the 8- to 16-cell stage were evaluated by our biodynamic imaging system to assess their energy status, after which they were lysed and their ATP contents were determined by means of a bioluminescence assay. A total of 68 embryos (32 treated with the inhibitor and 36 control) were evaluated. The ATP content analysis showed that the control embryos had significantly more ATP than those treated with sodium azide as determined by Student's t-test (5.04±1.07 vs. 1.31±0.57; P&lt;0.05). A correlative study was then completed where biodynamic biomarkers were used to classify embryos to estimate the ability of biodynamic imaging to identify embryos with high or low energy status. A set of 13 biomarkers representing each embryo as a feature vector was used to train a classifier. We found that the cross-validated classifier had a sensitivity and specificity of ~80%. In addition, a receiver-operator curve constructed by varying the ATP threshold of the independent bioluminescence assay had an area-under-the-curve of 0.81. These results indicate that biodynamic imaging is able to determine the energy status of the embryos noninvasively and has great potential in the assessment of embryo viability.

An integrative correlation of myopathology, phenotype and genotype in late onset Pompe disease

AIMS

Pompe disease is caused by pathogenic mutations in the alpha 1,4-glucosidase (GAA) gene and in patients with late onset Pome disease (LOPD), genotype-phenotype correlations are unpredictable. Skeletal muscle pathology includes glycogen accumulation and altered autophagy of various degrees. A correlation of the muscle morphology with clinical features and the genetic background in GAA may contribute to the understanding of the phenotypic variability.

METHODS

Muscle biopsies taken before enzyme replacement therapy were analysed from 53 patients with LOPD. On resin sections, glycogen accumulation, fibrosis, autophagic vacuoles and the degree of muscle damage (morphology-score) were analysed and the results were compared with clinical findings. Additional autophagy markers microtubule-associated protein 1A/1B-light chain 3, p62 and Bcl2-associated athanogene 3 were analysed on cryosections from 22 LOPD biopsies.

RESULTS

The myopathology showed a high variability with, in most patients, a moderate glycogen accumulation and a low morphology-score. High morphology-scores were associated with increased fibrosis and autophagy highlighting the role of autophagy in severe stages of skeletal muscle damage. The morphology-score did not correlate with the patient's age at biopsy, disease duration, nor with the residual GAA enzyme activity or creatine-kinase levels. In 37 patients with LOPD, genetic analysis identified the most frequent mutation, c.-32-13T>G, in 95%, most commonly in combination with c.525delT (19%). No significant correlation was found between the different GAA genotypes and muscle morphology type.

CONCLUSIONS

Muscle morphology in LOPD patients shows a high variability with, in most cases, moderate pathology. Increased pathology is associated with more fibrosis and autophagy.

Reducing the impact of geometric errors in flow computations using velocity measurements

Numerical blood flow simulations are typically set up from anatomical medical images and calibrated using velocity measurements. However, the accuracy of the computational geometry itself is limited by the resolution of the anatomical image. We first show that applying standard no-slip boundary conditions on inaccurately extracted boundaries can cause large errors in the results, in particular the pressure gradient. In this work, we therefore propose to augment the flow model calibration by slip/transpiration boundary conditions, whose parameters are then estimated using velocity measurements. Numerical experiments show that this methodology can considerably improve the accuracy of the estimated pressure gradients and 3D velocity fields when the vessel geometry is uncertain.

Biodynamic optical assay for embryo viability

Early stage porcine parthenogenetic embryos were evaluated for metabolic activity using a biodynamic microscope (BDM) that images dynamic light scattering using low-coherence digital holography. The microscope has a 45-deg illumination configuration that reduces specular background for the imaging of small translucent samples. The off-axis illumination is compatible with coherence-gated imaging because of volumetric light scattering in which the coherence plane is tilted at half the illumination angle in a three-dimensional tissue target. The BDM was used to profile the viability of porcine parthenotes with normal and with inhibited mitochondrial adenosine triphosphate (ATP) production using Doppler fluctuation spectroscopy. The ATP concentrations in the parthenotes, which are indicative of developmental potential, were validated by a conventional bioluminescence assay. Biodynamic classifications achieved ∼80  %   accuracy correlating sample ATP treatment, providing a quick, label-free surrogate measurement to replace invasive metabolic assays as a candidate for evaluating quality of early embryos in the assisted reproductive technology setting.

The critical size of a defect in the glenoid causing anterior instability of the shoulder after a Bankart repair, under physiological joint loading

Aims

Patients with recurrent anterior dislocation of the shoulder commonly have an anterior osseous defect of the glenoid. Once the defect reaches a critical size, stability may be restored by bone grafting. The critical size of this defect under non-physiological loading conditions has previously been identified as 20% of the length of the glenoid. As the stability of the shoulder is load-dependent, with higher joint forces leading to a loss of stability, the aim of this study was to determine the critical size of an osseous defect that leads to further anterior instability of the shoulder under physiological loading despite a Bankart repair.

Patients and Methods

Two finite element (FE) models were used to determine the risk of dislocation of the shoulder during 30 activities of daily living (ADLs) for the intact glenoid and after creating anterior osseous defects of increasing magnitudes. A Bankart repair was simulated for each size of defect, and the shoulder was tested under loading conditions that replicate in vivo forces during these ADLs. The critical size of a defect was defined as the smallest osseous defect that leads to dislocation.

Results

The FE models showed a high risk of dislocation during ADLs after a Bankart repair for anterior defects corresponding to 16% of the length of the glenoid.

Conclusion

This computational study suggests that bone grafting should be undertaken for an anterior osseous defect in the glenoid of more than 16% of its length rather than a solely soft-tissue procedure, in order to optimize stability by restoring the concavity of the glenoid.

Diffuse periostitis as the primary presenting radiological finding in an AML patient with disease relapse

Acute myelogenous leukemia is a hematologic malignancy defined by the presence of myeloid blasts causing bone marrow infiltration. Evaluation and workup of acute myelogenous leukemia is based on comprehensive medical history, physical examination, laboratory evaluation, and bone marrow sampling. Magnetic resonance (MR) imaging is the study of choice in the evaluation of this disease including the initial evaluation, treatment follow-up, and complications. Herein, we report a case of relapse of the acute myelogenic leukemia in an adult patient who presented with diffuse periostitis in his lower extremities diagnosed on MR imaging and confirmed on Technetium bone scan, which also showed periostitis along the bilateral humeri. To our knowledge, this was not previously reported in the English literature.

Biodynamic digital holography of chemoresistance in a pre-clinical trial of canine B-cell lymphoma

Biodynamic digital holography was used to obtain phenotypic profiles of canine non-Hodgkin B-cell lymphoma biopsies treated with standard-of-care chemotherapy. Biodynamic signatures from the living 3D tissues were extracted using fluctuation spectroscopy from intracellular Doppler light scattering in response to the molecular mechanisms of action of therapeutic drugs that modify a range of internal cellular motions. The standard-of-care to treat B-cell lymphoma in both humans and dogs is a combination CHOP therapy that consists of doxorubicin, prednisolone, cyclophosphamide and vincristine. The proportion of dogs experiencing durable cancer remission following CHOP chemotherapy was 68%, with 13 out of 19 dogs responding favorably to therapy and 6 dogs failing to have progression-free survival times greater than 100 days. Biodynamic signatures were found that correlate with inferior survival times, and biomarker selection was optimized to identify specific Doppler signatures related to chemoresistance. A machine learning classifier was constructed based on feature vector correlations and linear separability in high-dimensional feature space. Hold-out validation predicted patient response to therapy with 84% accuracy. These results point to the potential for biodynamic profiling to contribute to personalized medicine by aiding the selection of chemotherapy for cancer patients.

Abstract 1541: Heterogeneous response to platinum in metastatic ovarian cancer detectable by biodynamic imaging

The mechanisms by which tumors develop multi-drug resistance are not well understood. Biodynamic imaging (BDI) is a label-free assay that detects phenotypic response of ex vivo tissue to chemotherapeutic drugs. In the current study, we used BDI to measure the response of primary and metastatic ovarian tumors to cisplatin. Xenografts from two human ovarian cancer cell lines, A2780 and SKOV3, were grown orthotopically in the ovaries of nude mice and allowed to metastasize in the peritoneal space. Primary and metastatic tumors were harvested and tested for response to 25 μM cisplatin by using BDI. Sensitivity was assessed through selected response biomarkers. Metastatic tumors of the platinum-sensitive A2780 cell line showed 20% decrease in sensitivity to cisplatin compared with the response of the primary tumors, while the less sensitive SKOV3 tumors exhibited a 6% decrease in response of metastatic vs. primary tumors. In parallel, RNA sequencing profiled primary ovarian and metastatic implants. Differential gene expression was detected in primary tumors vs. metastatic sites. Genes upregulated in metastases include TIMP3, WNT2, OSR1, elastin (SKOV3 tumor model) and MMP1, MMP3, MMP10, MET, EGFR, PDGF-C (A2780 tumor model). The study demonstrates the ability of BDI to detect differences in drug sensitivity between primary and metastatic tumors and provides support for the association of metastasis and chemoresistance in ovarian cancer. Supported by NIH R01 EB016582.

Citation Format: Daniel Merrill, Hao Sun, Daniela Matei, Bakhtiyor Yakubov, John Turek, David Nolte. Heterogeneous response to platinum in metastatic ovarian cancer detectable by biodynamic imaging. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1541.

Height Resolution of Antibody Spots Measured by Spinning-Disk Interferometry on the BioCD

Spinning-disc interferometry (SDI) is a high-speed laser scanning approach to surface metrology that uses common-path interferometry to measure protein spots on a BioCD disk. The measurement sensitivity depends on the scanning pitch and on the time-base. Based on high-resolution laser scanning images of printed antibody spots, we quantify the protein sensitivity as a function of the scan parameters. For smoothly printed antibody spots scanned with a transverse spatial resolution of 1 μm, the surface height precision for a single 100 μm diameter protein spot is approximately 1 pm. This detection sensitivity sets the fundamental limit of detection for label-free BioCD biosensors performing immunoassays.

Intracellular Doppler Signatures of Platinum Sensitivity Captured by Biodynamic Profiling in Ovarian Xenografts

Three-dimensional (3D) tissue cultures are replacing conventional two-dimensional (2D) cultures for applications in cancer drug development. However, direct comparisons of in vitro 3D models relative to in vivo models derived from the same cell lines have not been reported because of the lack of sensitive optical probes that can extract high-content information from deep inside living tissue. Here we report the use of biodynamic imaging (BDI) to measure response to platinum in 3D living tissue. BDI combines low-coherence digital holography with intracellular Doppler spectroscopy to study tumor drug response. Human ovarian cancer cell lines were grown either in vitro as 3D multicellular monoculture spheroids or as xenografts in nude mice. Fragments of xenografts grown in vivo in nude mice from a platinum-sensitive human ovarian cell line showed rapid and dramatic signatures of induced cell death when exposed to platinum ex vivo, while the corresponding 3D multicellular spheroids grown in vitro showed negligible response. The differences in drug response between in vivo and in vitro growth have important implications for predicting chemotherapeutic response using tumor biopsies from patients or patient-derived xenografts.

Point-of-Care Clinical Ultrasound for Medical Students

PURPOSE

Our institution has recently implemented a point-of-care (POC) ultrasound training program, consisting of an e-learning course and systematic practical hands-on training. The aim of this prospective study was to evaluate the learning outcome of this curriculum.

MATERIALS AND METHODS

16 medical students with no previous ultrasound experience comprised the study group. The program covered a combination of 4 well-described point-of-care (POC) ultrasound protocols (focus assessed transthoracic echocardiography, focused assessment with sonography in trauma, lung ultrasound, and dynamic needle tip positioning for ultrasound-guided vascular access) and it consisted of an e-learning course followed by 4 h of practical hands-on training. Practical skills and image quality were tested 3 times during the study: at baseline, after e-learning, and after hands-on training.

RESULTS

Practical skills improved for all 4 protocols; after e-learning as well as after hands-on training. The number of students who were able to perform at least one interpretable image of the heart increased from 7 at baseline to 12 after e-learning, p<0.01, and to all 16 students after hands-on-training, p<0.01. The number of students able to cannulate an artificial vessel increased from 3 to 8 after e-learning and to 15 after hands-on training.

CONCLUSION

Medical students with no previous ultrasound experience demonstrated a considerable improvement in practical skill after interactive e-learning and 4 h of hands-on training.

White matter damage is related to ataxia severity in SCA3

Spinocerebellar ataxia type 3 (SCA3) is the most frequent inherited cerebellar ataxia in Europe, the US and Japan, leading to disability and death through motor complications. Although the affected protein ataxin-3 is found ubiquitously in the brain, grey matter atrophy is predominant in the cerebellum and the brainstem. White matter pathology is generally less severe and thought to occur in the brainstem, spinal cord, and cerebellar white matter. Here, we investigated both grey and white matter pathology in a group of 12 SCA3 patients and matched controls. We used voxel-based morphometry for analysis of tissue loss, and tract-based spatial statistics (TBSS) on diffusion magnetic resonance imaging to investigate microstructural pathology. We analysed correlations between microstructural properties of the brain and ataxia severity, as measured by the Scale for the Assessment and Rating of Ataxia (SARA) score. SCA3 patients exhibited significant loss of both grey and white matter in the cerebellar hemispheres, brainstem including pons and in lateral thalamus. On between-group analysis, TBSS detected widespread microstructural white matter pathology in the cerebellum, brainstem, and bilaterally in thalamus and the cerebral hemispheres. Furthermore, fractional anisotropy in a white matter network comprising frontal, thalamic, brainstem and left cerebellar white matter strongly and negatively correlated with SARA ataxia scores. Tractography identified the thalamic white matter thus implicated as belonging to ventrolateral thalamus. Disruption of white matter integrity in patients suffering from SCA3 is more widespread than previously thought. Moreover, our data provide evidence that microstructural white matter changes in SCA3 are strongly related to the clinical severity of ataxia symptoms.

Live tissue viability and chemosensitivity assays using digital holographic motility contrast imaging

Holographic optical coherence imaging is an en face form of optical coherence tomography that uses low-coherence digital holography as a coherence gate to select light from a chosen depth inside scattering tissue. By acquiring successive holograms at a high camera frame rate at a fixed depth, dynamic speckle provides information concerning dynamic light scattering from intracellular motility. Motility contrast imaging (MCI) uses living motion as a label-free and functional biomarker. MCI provides a new form of viability assay and also is applicable for proliferation and cytotoxicity assays. The results presented here demonstrate that low-coherence digital holography can extract viability information from biologically relevant three-dimensional (3D) tissue based on multicellular tumor spheroids by moving beyond the format of two-dimensional cell culture used for conventional high-content analysis. This paper also demonstrates the use of MCI for chemosensitivity assays on tumor exgrafts of excised ovarian cancer tumors responding to standard-of-care cisplatin chemotherapy. This ex vivo application extends the applicability of MCI beyond 3D tissue culture grown in vitro.

Spinocerebellar ataxia type 17 associated with an expansion of 42 glutamine residues in TATA-box binding protein gene

BACKGROUND

Spinocerebellar ataxia type 17 (SCA17) is caused by abnormal expansions of CAG/CAA trinucleotides within the TATA-box binding protein gene (TBP). The currently accepted critical threshold of abnormal expansions is ≥43.

OBJECTIVE

To investigate the minimal CAG/CAA expansion within the TBP in SCA17.

RESULTS

285 patients with autosomal-dominant ataxia were examined, and abnormal or borderline expansions of CAG/CAA within TBP in eight cases were found. Of those, four patients from three families had exactly 42 CAG/CAA trinucleotides, that is, one codon less than the currently accepted critical threshold of 43. The four patients presented with a relatively benign phenotype. All had dysdiadochokinesia and dysarthria. Mild gait ataxia was observed in three of the four patients.

CONCLUSION

The reference definition of at least 43 CAG/CAA codons for pathological SCA17 alleles should be lowered to 42.

Mass-transport limitations in spot-based microarrays

Mass transport of analyte to surface-immobilized affinity reagents is the fundamental bottleneck for sensitive detection in solid-support microarrays and biosensors. Analyte depletion in the volume adjacent to the sensor causes deviation from ideal association, significantly slows down reaction kinetics, and causes inhomogeneous binding across the sensor surface. In this paper we use high-resolution molecular interferometric imaging (MI2), a label-free optical interferometry technique for direct detection of molecular films, to study the inhomogeneous distribution of intra-spot binding across 100 micron-diameter protein spots. By measuring intra-spot binding inhomogeneity, reaction kinetics can be determined accurately when combined with a numerical three-dimensional finite element model. To ensure homogeneous binding across a spot, a critical flow rate is identified in terms of the association rate k(a) and the spot diameter. The binding inhomogeneity across a spot can be used to distinguish high-affinity low-concentration specific reactions from low-affinity high-concentration non-specific binding of background proteins.

Differential phase-contrast BioCD biosensor

Common-path differential phase-contrast interferometry measures the spatial gradient of surface dipole density on a bio-optical compact disk (BioCD) and is sensitive to small changes in dipole density following molecular binding of target molecules out of solution. The recognition molecules are antibody IgG proteins that are deposited in periodic patterns on the BioCD using soft lithography or photolithography on the silanized silica surfaces of dielectric mirrors. Spatial carrier-wave sideband demodulation extracts the slowly varying protein envelope that modulates the protein carrier frequency. The experimental interferometric profilometry has surface height sensitivity down to 20 pm averaged over a lateral scale of 70 microm with a corresponding scaling mass sensitivity limit of 1.5 pg/mm. Under the conditions of an IgG immunoassay with background changes caused during incubation, the scaling mass sensitivity is approximately 7 pg/mm. A saturated reverse immunoassay performed with IgG at 100 ng/ml showed false positive and false negative rates of 0.2%.

Stages of sleep pathology in spinocerebellar ataxia type 2 (SCA2)

BACKGROUND

Autosomal dominant spinocerebellar ataxia type 2 (SCA2) bears clinical and neuropathologic similarities to sporadic multisystem atrophy (MSA) or Parkinson disease, in which sleep pathology is well documented. However, those clinical entities have a marked variability of the reported sleep disturbances, and their etiology is heterogeneous. In contrast, the study of SCA2 provides an opportunity to examine a molecularly homogeneous patient group, in which disease stages can be defined not only based on disease duration and ataxia scores, but also with regard to modulatory effects of mutation size.

OBJECTIVE

To examine the presence and progression of sleep pathology in SCA2.

METHODS

We analyzed eight patients with disease durations of 3 to 31 years, all with medium size SCA2 expansions (CAG 38 to 49), using clinical scores, sleep interviews, and video-polysomnography (VPSG) recordings.

RESULTS

Almost all patients reported good subjective sleep quality and negated incidents of REM behavior disorder (RBD). At early disease stages, however, REM without atonia in four patients' VPSG suggested subclinical RBD. This was accompanied by a consistent reduction of REM density. In three patients at later SCA2 stages, REM sleep was undetectable, whereas slow wave sleep (SWS) was markedly increased at the cost of light sleep. Periodic leg movements, apnea, or hypopnea were not prominent.

CONCLUSIONS

Progressive loss of dream recall in spinocerebellar ataxia type 2 was found and correlated with stages of REM more than non-REM pathology in video-polysomnography. These stages correspond to the progressive atrophy from the pons, nigrostriatal projection, and locus ceruleus to the thalamus.

High-Speed Interferometric Detection of Label-Free Immunoassays on the Biological Compact Disc

Background: We describe a direct-detection immunoassay that uses high-speed optical interferometry on a biological compact disc (BioCD).

Methods: We fabricated phase-contrast BioCDs from 100-mm diameter 1.1-mm thick borosilicate glass disks coated with a 10-layer dielectric stack of Ta2O5/SiO2 that serves as a mirror with a center wavelength at 635 nm. The final layer is a λ/4 layer of SiO2 onto which protein patterns are immobilized through several different chemical approaches. Protein on the disc is scanned by a focused laser spot as the disc spins. Interaction of the light with the protein provides both a phase-modulated signal and a local reference that are combined interferometrically to convert phase into intensity. A periodic pattern of protein on the spinning disc produces an intensity modulation as a function of time that is proportional to the surface-bound mass. The binding of antigen or antibodies is detected directly, without labels, by a change in the interferometric intensity. The technique is demonstrated with a reverse assay of immobilized rabbit and mouse IgG antigen incubated against anti-IgG antibody in a casein buffer.

Results: The signal increased with increased concentration of analyte. The current embodiment detected a concentration of 100 ng/L when averaged over ∼3000 100-micron-diameter protein spots.

Conclusions: High-speed interferometric detection of label-free protein assays on a rapidly spinning BioCD is a high-sensitivity approach that is amenable to scaling up to many analytes.

Point-of-care biosensor systems for cancer diagnostics/prognostics

With the growing number of fatalities resulting from the 100 or so cancer-related diseases, new enabling tools are required to provide extensive molecular profiles of patients to guide the clinician in making viable diagnosis and prognosis. Unfortunately with cancer-related diseases, there is not one molecular marker that can provide sufficient information to assist the clinician in making effective prognoses or even diagnoses. Indeed, large panels of markers must typically be evaluated that cut across several different classes (mutations in certain gene fragments--DNA; over/under-expression of gene activity as monitored by messenger RNAs; the amount of proteins present in serum or circulating tumor cells). The classical biosensor format (dipstick approach for monitoring the presence of a single element) is viewed as a valuable tool in many bioassays, but possesses numerous limitations in cancer due primarily to the single element nature of these sensing platforms. As such, if biosensors are to become valuable tools in the arsenal of the clinician to manage cancer patients, new formats are required. This review seeks to provide an overview of the current thinking on molecular profiling for diagnosis and prognosis of cancers and also, provide insight into the current state-of-the-art in the biosensor field and new strategies that must be considered to bring this important technology into the cancer field.

An autosomal dominant ataxia maps to 19q13: Allelic heterogeneity of SCA13 or novel locus?

The autosomal dominant spinocerebellar ataxias (ADCAs) represent a growing and heterogeneous disease phenotype. Clinical characterization of a three-generation Filipino family segregating a dominant ataxia revealed cerebellar signs and symptoms. After elimination of known spinocerebellar ataxia (SCA) loci, a genome-wide linkage scan revealed a disease locus in a 4-cM region of 19q13, with a 3.89 lod score. This region overlaps and reduces the SCA13 locus. However, this ADCA is clinically distinguishable from SCA13.

Simultanes nichtinvasives Monitoring mit Laser-Doppler-Flussmessung und Gewebespektrometrie bei fasziokutanen Radialislappen und osteokutanen Fibulatransplantaten

AIM

In the literature currently available monitoring devices are usually divided into two major groups: those for monitoring perfusion and those for measuring tissue oxygenation. The O(2)C (oxygen to see) system combines these two ways of monitoring free flap viability. The aim of this prospective study was to determine the necessity of flap revision and when unnecessary revision can be avoided. Another point of interest was the question of whether critical values for the successful course of free flaps could be defined and in addition whether such values would differ for different flap types.

PATIENTS AND METHODS

In a prospective study 82 free flaps (61 radial forearm flaps and 21 fibula flaps) were monitored with the O(2)C monitoring unit. Measurements were carried out intraoperatively and postoperatively up to 14 days.

RESULTS

Perfusion compromise occurred in 12 (14.6%) of 82 monitored free flaps. Operative exploration was performed in seven cases, in five of them successfully. Five flaps (three radial forearm and two fibula flaps) were lost due to vascular compromise, which led to an overall success rate of 93.4%. Venous congestion was identified by a rapid increase in hemoglobin concentration of more than 30%. An abrupt decline of blood flow and hemoglobin oxygenation indicated arterial occlusion. Vascular complications were detected in all cases prior to clinical assessment with no false positive or negative results. For radial forearm flaps a hemoglobin oxygenation of 15%, a superficial flow of 10 AU, and a deep flow of 20 AU were identified as minimum values for flap viability. For fibula flaps a hemoglobin oxygenation of 10%, a superficial flow of 5 AU, and a deep flow of 15 AU were determined as minimum values.

CONCLUSION

O(2)C combines laser Doppler flowmetry and tissue spectrophotometry and for the first time allows simultaneous measurement of the microcirculatory parameters including blood flow, flow velocity, hemoglobin concentration, and hemoglobin oxygenation. We found this new noninvasive technique to be a reliable and accurate method for evaluating flap viability and improving the success rate in free flap transfer.

Reversible ischaemia after raising a radial forearm flap with ulceration of three fingers in a cigarette smoker

The radial forearm flap is a standard method for the reconstruction of intraoral defects of soft tissues. We report the case of a middle-aged man who developed ischaemia in three fingers after a fasciocutaneous radial flap had been raised. The preoperative Allen test to diagnose occlusion of radial or ulnar artery was satisfactory. Soon after the operation the patient resumed smoking and four weeks later he developed ulcers on the thumb, index, and middle fingers. Only after he had stopped smoking and been given acetylsalicylic acid and heparin did blood flow and capillary hemoglobin oxygenation increase. As a result, his radial fingers recovered completely.

Attenuation of Leukocyte Sequestration by Selective Blockade of PECAM-1 or VCAM-1 in Murine Endotoxemia

BACKGROUND

Molecular mechanisms regulating leukocyte sequestration into the tissue during endotoxemia and/or sepsis are still poorly understood. This in vivo study investigates the biological role of murine PECAM-1 and VCAM-1 for leukocyte sequestration into the lung, liver and striated skin muscle.

METHODS

Male BALB/c mice were injected intravenously with murine PECAM-1 IgG chimera or monoclonal antibody (mAb) to VCAM-1 (3 mg/kg body weight); controls received equivalent doses of IgG2a (n = 6 per group). Fifteen minutes thereafter, 2 mg/kg body weight of Salmonella abortus equi endotoxin was injected intravenously. At 24 h after the endotoxin challenge, lungs, livers and striated muscle of skin were analyzed for their myeloperoxidase activity. To monitor intravital leukocyte-endothelial cell interactions, fluorescence videomicroscopy was performed in the skin fold chamber model of the BALB/c mouse at 3, 8 and 24 h after injection of endotoxin.

RESULTS

Myeloperoxidase activity at 24 h after the endotoxin challenge in lungs (12,171 +/- 2,357 mU/g tissue), livers (2,204 +/- 238 mU/g) and striated muscle of the skin (1,161 +/- 110 mU/g) was significantly reduced in both treatment groups as compared to controls, with strongest attenuation in the PECAM-1 IgG treatment group. Arteriolar leukocyte sticking at 3 h after endotoxin (230 +/- 46 cells x mm(-2)) was significantly reduced in both treatment groups. Leukocyte sticking in postcapillary venules at 8 h after endotoxin (343 +/- 69 cells/mm2) was found reduced only in the VCAM-1-mAb-treated animals (215 +/- 53 cells/mm2), while it was enhanced in animals treated with PECAM-1 IgG (572 +/- 126 cells/mm2).

CONCLUSION

These data show that both PECAM-1 and VCAM-1 are involved in endotoxin-induced leukocyte sequestration in the lung, liver and muscle, presumably through interference with arteriolar and/or venular leukocyte sticking.

[Importance of microcirculation in plastic surgery]

The article summarizes distinct microcirculatory models for use in surgical research with a special interest to plastic surgery. Methods for the quantitative analysis of the microcirculation in burns, flaps and wounds are presented. Vascularization of biomaterials can be observed by means of the dorsal skinfold chamber model in hamsters and mice. Developing capillary sprouts can be assessed by means of videomicroscopy and angiogenetic drugs can be tested using this model. Hairless mice allow for direct, long-term observation of the microcirculation in burns as well as during healing of dermal wounds. The pathophysiology of diabetic wound healing can also be studied. A mouse model to assess flap microcirculation during ischemia/reperfusion injury with special emphasis on platelet/endothelium interaction in vivo is described. Platelets adherent to the inner vessel wall are known to trigger compromised perfusion in flaps. The model allows us to test anti-thrombotic drugs. The use of a special microscopic device (OPS imaging) allows us to study the microcirculation at sites of burn injury and chronic wounds in humans. Microcirculatory research in plastic surgery has increased the understanding of the pathophysiology of vascularization of biomaterials, wound healing and ischemia/reperfusion.

Limitationen der Blutversorgung des Hautlappens beim Facelifting

BACKGROUND

Besides nerve injuries or hematomas, one of the main risks of face lift surgery is the development of skin necrosis. We therefore investigated which arteries contribute to the blood supply of the face lift skin flap and how extensively mobilization can be performed before arterial cutaneous circulation is endangered.

MATERIAL AND METHOD

In six cadavers, selective dye injections into the branches of the carotid external artery were performed to determine the location of their vascular territories in relation to the face lift region. In another 12 cadavers, face lift flaps were raised with different extension of the undermined skin area before dye injections were performed.

RESULTS

It was shown that the facial artery provides blood supply to the area of the face lift flap by perforating vessels in the paranasal, perioral and submental regions and the transverse facial artery by a perforating vessel below the malar bone prominence. Although the perforating vessel of the transverse facial artery was transected by standard mobilization, the face lift flaps were sufficiently perfused via the paranasal and perioral perforating vessels of the facial artery alone.

CONCLUSION

We conclude that undermining of the face lift flap should not exceed the nasolabial fold to preserve the perforating vessels of the facial artery in the centrofacial region.

Botulinumtoxin zur Behandlung des gustatorischen Schwitzens

BACKGROUND

Botulinum toxin A has meanwhile become a proven method for treatment of gustatory sweating (focal hyperhidrosis, Frey's syndrome). Clear-cut recommendations regarding dosage of botulinum toxin A in Frey's syndrome are currently not available. The aim of this prospective randomized study therefore was to investigate botulinum toxin A with respect to its efficacy in Frey's syndrome, the ideal dose yielding maximal duration of the effect, and patient contentedness as well as unwanted side effects in patients of the Clinic of OMF Surgery at the Ruhr-University of Bochum.

PATIENTS AND METHOD

Twenty patients suffering from severe Frey's syndrome as a result of operations of the parotid gland were examined with the starch iodine test according to Minor. The gustatory skin areas were re-examined after intracutaneous injection of botulinum toxin A for up to 1 year. The patients ( n=20) were randomly assigned to two different treatment groups (group I: 2 MU/cm(2), n=10; group II: 3 MU/cm(2), n=10).

RESULTS

Mean sweating skin areas in the two treatment groups ranged between 39+/-9 and 32+/-12 cm(2), respectively. A single injection of 3 MU botulinum toxin A resulted in a nearly complete blockade of gustatory sweating for the observation period of 1 year. In the group treated with 2 MU botulinum toxin A, 44% of the total gustatory skin areas were still sweating, thus necessitating a second injection of botulinum toxin A in these patients.

CONCLUSION

Intracutaneous injection of botulinum toxin A represents a highly effective and minimally invasive procedure for the treatment of Frey's syndrome. This study shows for the first time that a dosage of 3 MU/cm(2) of botulinum toxin A achieves a complete and reliable blockade of gustatory sweating lasting for at least 12 months. This dose may therefore be recommended for treatment of this syndrome.

[Management of zygomatic fractures via a transconjunctival approach with lateral canthotomy while preserving the lateral ligament]

INTRODUCTION

This study reports on a modified approach to treat zygomatic fracture. For the surgical approach, a transconjunctival incision and, instead of a lateral canthotomy, a superficial incision of the skin and subcutaneous tissue was used, preserving the lateral ligament. The results are compared with those of previous techniques, especially the subciliary incision.

PATIENTS

In a prospective study, 30 patients (9 females and 21 males, mean age 32.1 years) with zygomatic fractures were operated using this approach. Mean follow-up time was 6 months after removal of the plates. Fractures were caused by trauma due to fighting, bicycle falls, or sport accidents. Follow-up radiographs were used to evaluate the position of the zygoma after reduction and rigid fixation.

RESULTS

Reduction and rigid fixation of the fractures were possible to perform in all cases. The access to the orbital floor and the exposure of the inferior and lateral rim were satisfactory and an additional latero-orbital cut was not necessary. The disadvantage of the complete incision of the lateral ligament with the necessity of intraoperative refixation and possible ectropium of the eyelid could be avoided. Injuries or infections of the cornea or the bulbus did not occur. Postoperative complications such as scar formation resulting in entropium or ectropium were not seen.

CONCLUSION

These results show that the transconjunctival approach with lateral superficial incision preserving the lateral ligament for treatment of zygomatic fractures is satisfactory in all cases of rigid fixation of both inferior and lateral rims. Because of its esthetic and functional advantages this approach has become standard in our department.

Restoration of blood flow and evaluation of corresponding angiogenic events by scanning electron microscopy after a single dose of VEGF in a model of peripheral vascular disease

The angiogenic effect of vascular endothelial growth factor (VEGF) has typically been assessed by indirect methods, including microsphere injection and angiography. Here, we use 3-D scanning electron microscopy (SEM) to directly visualize patterns of angiogenesis after a single bolus administration of VEGF in a model of peripheral vascular ischemia. Hind limb ischemia was induced by subcutaneous turniquet implantation in adult Wistar rats. The control group (group A, n = 10) was left untreated, group B (n = 10) received a single dose of VEGF (50 microg) injected in the peroneus muscle. LASER Doppler was applied for blood flow measurements. Animals were sacrificed on day 14 after ischemia induction and vascular casting was performed. Angiogenetic events such as 'tiny lateral sprouts', arcus formations', confluences and the angle of sprouting were assessed by SEM. Significant capillary sprouting was observed in both groups. VEGF-treated limbs demonstrated higher degrees of capillary growth (P = 0.01) and flow recovery (P = 0.028). 3-D-SEM showed sprouts to be more frequent in group B. Tiny lateral sprouts, which always left the mother vessel at an angle of 90 degrees and which were of small diameter and lacked imprints of endothelial cell nuclei, were more frequent in the VEGF-treated group (P = 0.018). Arcus formation was significantly higher in the treated group (P = 0.02). We have developed a simple and effective experimental model of ischemia. For the study of angiogenic phenomena, 3-D imaging of the microvasculature offers a direct and conclusive method for the study of angiogenic events.

Time gated fluorescence spectroscopy in Barrett's oesophagus

BACKGROUND AND AIMS

Specialised intestinal metaplasia and its dysplastic transformation, which precedes cancer in Barrett's oesophagus cannot be differentiated in standard gastroscopy. The aim of this study was to investigate whether laser induced protoporphyrin IX fluorescence permits the detection of specialised intestinal metaplasia and dysplasia during endoscopy and to take biopsy specimens in a guided rather than random manner.

METHODS

In 53 patients with Barrett's oesophagus 5-aminolaevulinic acid was sprayed on the mucosa. Approximately 60 to 120 minutes later, biopsy specimens were taken based on point-like measurements of delayed fluorescence intensity ratios of protoporphyrin IX in vivo. Two independent pathologists examined the 596 biopsy specimens taken, 168 of which were selected to be investigated by a third pathologist. Among these specimens only those (n=141) with a consensus diagnosis by at least two pathologists and p53 expression as additional marker were included in the analysis.

RESULTS

The median of normalised fluorescence intensity (ratio of delayed PpIX fluorescence intensity to immediate autofluorescence intensity) in non-dysplastic specialised intestinal metaplasia (0.51, 68% CI 0.09 to 1.92) and low grade dysplasia (1.89, 68% CI 0.55 to 3.92) differed significantly (p<0.005). Dysplasia was detected at a rate 2.8-fold higher compared with screening endoscopy despite taking fewer specimens. In addition, three early cancers were detected for the first time. Moreover, this method permitted differentiation of specialised intestinal metaplasia from junctional or gastric-fundic type epithelium (p<0.013).

CONCLUSIONS

For the first time it was possible to differentiate low grade dysplasia from non-dysplastic Barrett's mucosa during endoscopy based on delayed laser induced fluorescence endoscopy of PpIX. Furthermore, the method helps to detect specialised intestinal metaplasia in short Barrett's oesophagus.

[Oxygen-carrying solutions improve tissue oxygenation in striated skin muscle subjected to critical ischemia]

AIM

The aim of the present study was to investigate the effects of the oxygen-carrying hemoglobin solution DCLHb (diaspirin-crosslinked hemoglobin) on microvascular perfusion and tissue oxygenation in striated skin muscle after the induction of critical ischemia followed by reperfusion.

MATERIAL AND METHODS

Using intravital fluorescence microscopy the functional capillary density was analyzed in the striated skin muscle of Syrian golden hamsters before the induction of a 4-h period of ischemia and again after 0.5 h, 2 h and 24 h of reperfusion ( n=8 in each group). In other animals ( n=8 in each group), the identical protocol was applied to determine tissue oxygenation by means of the multi-wire surface electrode (MDO, Eschweiler, Kiel, Germany). Animals in the treatment group ( n=8) received a bolus infusion of 5 ml of DCLHb per kg of body wt. (10 g/dl; Baxter, Ill., USA) 15 min before reperfusion. Control animals ( n=8) received equivalent volumes of isotonic saline (Braun, Melsungen, Germany). RESULTS. Functional capillary density was dramatically reduced in control animals, while in DCLHb-treated animals significantly higher values were observed. Efficient restoration of tissue PO(2) was also seen in DCLHb-treated animals and not in control animals.

CONCLUSIONS

These results show that the oxygen-carrying solution DCLHb is significantly more efficient than the commonly used crystalloid solutions in restoration of tissue PO(2) after ischemia-reperfusion. The use of this solution therefore appears promising as a means of protecting the tissue put at risk by ischemia from reperfusion damage.

ACRC codes for a novel nuclear protein with unusual acidic repeat tract and maps to DYT3 (dystonia parkinsonism) critical interval in xq13.1

We searched for novel genes as candidates of X-linked dystonia parkinsonism (XDP) in the critical interval of Xq13.1 that harbors the disease locus (DYT3). A gene, ACRC (acidic repeat containing), was discovered by a combination of in silico and "wet" experiments. ACRC is composed of at least 12 exons and 11 introns. It is expressed in all tissues tested, including skeletal muscle, liver, kidney, pancreas, heart, lung, and brain. Highest levels of expression are found in skeletal muscle. The ACRC protein is characterized by a previously undescribed acidic repeat tract of 21 units of 8-10 amino acids. The N-terminal portion of the protein is highly acidic (pI=3.2), and the C-terminal region is basic (pI=10.2). There are nuclear localization signals in its C-terminal portion. Extensive mutation analysis of the transcribed region of the gene, including intron-exon boundaries and the 5' and 3' untranslated intervals, did not reveal a mutation in XDP patients. Exclusion of a mutation in the transcribed portion of this and all other known genes within the DYT3 critical interval suggests that XDP is most likely caused by a mutation in a regulatory region of a gene within the critical interval, or by a structural rearrangement.

Changes in the local blood and lymph microcirculation in response to direct mechanical trauma applied to leg: in vivo study in an animal model

BACKGROUND

The aim of this study was to investigate changes in the blood microcirculation of skin, subcutaneous tissue, and striated muscle, and the venous and lymphatic outflow from hind limb, after a standardized mechanical trauma.

METHODS

Trauma, defined as 50% of the minimal energy needed for tibia fracture (3.7 J/g), was applied to the leg of hairless mice. Intravenously injected fluorescein isothiocyanate-dextran 150 kDa and Rhodamine-6G were used for intra-vital fluorescence microscopy of blood vessels. Lymphatics were stained with fluorescein isothiocyanate-dextran injected into the footpad. A computer-assisted analysis system allowed measurement of the functional capillary density (FCD), vessel diameters, velocity of blood flow, and edema value expressed as extravasation index (EV). The percentage of slowly rolling and sticking leukocytes in postcapillary venules was estimated.

RESULTS

At the site of injury, trauma resulted in significant reduction of FCD in skin, subcutaneous tissue, and striated muscle. There were no significant differences in the vessel diameter (skin subcutaneous and muscle arterioles and venules, and superficial saphenous artery and vein) or velocity of blood flow (subcutaneous tissue and muscle venules). The EV increased significantly in muscle venules and was higher in muscles, subcutaneous tissue, and superficial saphenous veins than in controls (nonsignificantly). An increased percentage of slowly rolling and sticking leukocytes was noted in the superficial saphenous vein at the site of injury and proximal to it. The lymphatics remained patent, with faster visualization and increased summarized cross-sectional areas in traumatized extremities.

CONCLUSION

Early changes occurring in soft tissues in response to mechanical injury were characterized by reduction in FCD of skin and muscles, and less in subcutis; increased EV, reflecting leakage of macromolecules; increased percentage of slowly rolling and sticking leukocytes; maintenance of lymphatic vessel continuity; and increased lymph formation and flow rate.

Heparin protects local skin microcirculation in 210 minutes-long intravital microscopy observations under general anaesthesia

Prolonged immobilization of severely ill, bed-ridden patients results in formation of pressure ulcers following inappropriate tissue blood perfusion, and local activation of leukocyte - endothelial cell interactions (L/EC). Various treatment modalities were implemented to improve local microcirculation with controversial results. The aim of our study was to investigate the influence of heparin and buflomedil, drugs improving the microcirculation, on local skin blood perfusion using intravital fluorescent microscopy (IVM) technique.

MATERIAL AND METHODS

Experiments were carried out on 24 male hairless mice under inhalatory isofluran anaesthesia. Intravenous injection of FITC-dextran (150 kD, 5%) allowed to visualize capillaries during IVM, after immobilisation of hind limb, in an observation chamber. Observations were performed after i.v. injection of heparin (66 IU/kg b.w., n = 8) or buflomedil (6 mg/kg b.w., n = 8) 30, 120 and 210 minutes after chamber installation. Observations were recorded in 30 sec sequences on S-VHS tapes and evaluated using special software. Functional capillary density (FCD), defined as a total length of red cells perfused capillaries per observation field (expressed in cm/cm(2)), postcapillary venule diameters, and number of sticking leukocytes per 0.2 mm vessel length during 30 sec observation time, served as parameters of skin blood perfusion and activation of L/EC interactions.

RESULTS

A statistically significant decrease of FCD from 152.7 +/- 38.5 to 100.7 +/- 36.7 cm/cm (2) (p<0.05) was observed in control animals during 210 min lasting observation. Administration of heparin prevented decrease in FCD occurring in control animals during intravital microscopy, whereas buflomedil was found ineffective. Both drugs induced a nonsignificant reduction in the number of sticking leukocytes, whereas no changes in postcapillary venule diameters could be observed.

CONCLUSION

The results suggest a protective effect of heparin in clinical therapeutic doses against impairment of skin perfusion during IVM. This observation may justify a trial on the effects of heparin in prevention of development of pressure ulcers.

Protoporphyrin IX occurs naturally in colorectal cancers and their metastases

Colorectal cancers exhibit a red fluorescence. The nature of the responsible fluorophore and its eventual diagnostic potential were investigated. Thirty-three consecutive colorectal resection specimen, 32 of which with histologically confirmed cancer, and a total of 1053 palpable mesenteric nodes were fluorimetrically characterized ex vivo. Furthermore, frozen material from 28 patients was analyzed, selected for the availability of primary tumor material and metastatic tissue, e.g., lymphatic and liver metastases from the same patient. Biochemical characterization was carried out through chemical extraction and reversed phase high-performance liquid chromatography. The fluorescence spectra of tissues, tissue extracts, and standard solutions of porphyrins were determined using a pulsed solid-state laser system for excitation and an imaging polychromator, together with an intensified CCD camera for time-delayed observation. Protoporphyrin IX (PpIX) was identified as the predominant fluorophore in primary tumors and their metastases. The fluorophore occurred in the absence of necrosis and in sterile locations. In untreated cases (n = 24), PpIX fluorescence discriminates metastatically involved lymph nodes from all other palpable nodes with a sensitivity of 62% at a specificity of 78% (P < 0.0001). After neoadjuvant treatment of rectal cancer, the PpIX fluorescence level of the primary tumors was reduced and a discrimination of lymph nodes based on PpIX-fluorescence was impossible. We conclude that colorectal cancer metastases accumulate diagnostic levels of endogenous PpIX as a result of a tumor-specific metabolic alteration.