Imaging-based characterization of convective tissue properties

Convective transport is an important phenomenon for nanomedicine delivery. We present an imaging-based approach to recover tissue properties that are significant in the accumulation of nanoparticles delivered via systemic methods. The classical pharmacokinetic analysis develops governing equations for the particle transport from a first principle mass balance. Fundamentally, the governing equations for compartmental mass balance represent a spatially invariant mass transport between compartments and do not capture spatially variant convection phenomena. Further, the parameters recovered from this approach do not necessarily have direct meaning with respect to the governing equations for convective transport. In our approach, a framework is presented for directly measuring permeability in the sense of Darcy flow through porous tissue. Measurements from our approach are compared to an extended Tofts model as a control. We demonstrate that a pixel-wise iterative clustering algorithm may be applied to reduce the parameter space of the measurements. We show that measurements obtained from our approach are correlated with measurements obtained from the extended Tofts model control. These correlations demonstrate that the proposed approach contains similar information to an established compartmental model and may be useful in providing an alternative theoretical framework for parameterizing mathematical models for treatment planning and diagnostic studies involving nanomedicine where convection dominated effects are important.

Reliable detection of atrial fibrillation with a medical wearable under inpatient conditions (CoMMoD-A-fib)

Background

Atrial fibrillation (A-fib) is the most common arrhythmia; however, detection of A-fib is a challenge due to irregular occurrence.

Purpose

Evaluating feasibility and performance of a non-invasive medical wearable for detection of A-fib.

Methods

In the CoMMoD-A-fib trial admitted patients with a high risk for A-fib carried the wearable and an ECG Holter (control) in parallel over a period of 24 hours under not physically restricted conditions. The wearable with a tight-fit upper arm band employs a photoplethysmography (PPG) technology enabling a high sampling rate. Different algorithms (including a deep neural network) were applied to 5 min PPG datasets for detection of A-fib. Proportion of monitoring time automatically interpretable by algorithms (= interpretable time) was analyzed for influencing factors.

Results

In 102 inpatients (age 71.0±11.9 years; 52% male) 2306 hours of parallel recording time could be obtained; 1781 hours (77.2%) of these were automatically interpretable by an algorithm analyzing PPG derived intervals. Detection of A-Fib was possible with a sensitivity of 92.7% and specificity of 92.4% (AUC 0.96). Also during physical activity, detection of A-fib was sufficiently possible (sensitivity 90.1% and specificity 91.2%). Usage of the deep neural network improved detection of A-fib further (sensitivity 95.4% and specificity 96.2%). A higher prevalence of heart failure with reduced ejection fraction was observed in patients with a low interpretable time (p=0.080).

Conclusion

Detection of A-fib by means of an upper arm non-invasive medical wearable with a high resolution is reliably possible under inpatient conditions.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Internal grant program (PhD and Dr. rer. nat. Program Biomedicine) of the Faculty of Health at Witten/Herdecke University, Germany. HELIOS Kliniken GmbH (Grant-ID 047476), Germany

1350Outcome after diagnosis with hypertrophic cardiomyopathy: a nationwide study

Background

Patients with hypertrophic cardiomyopathy (HCM) are generally considered to have an increased morbidity and mortality due to symptomatic heart failure, atrial fibrillation, stroke and sudden cardiac death. Data reporting the mortality compared with background populations are however conflicting and primarily based on small cohorts from tertiary centers.

Purpose

We aimed to investigate whether a nationwide cohort of patients with HCM had an increased risk of death compared with a matched cohort derived from the general Danish population.

Methods

Using nationwide registries, we identified all patients with a first-time HCM diagnosis in Denmark between 2007 and 2016. Patients were matched 1:5 on age, sex and HCM diagnosis date to controls using risk set sampling. The study population was followed until death, emigration, or end of study period Jan. 1, 2017–whichever came first. Mortality was compared using Kaplan Meier plots and multivariable adjusted Cox proportional hazard analysis.

Results

We identified 3010 patients diagnosed with HCM (53.8% male) per registry codes. Men were on average 8.5 years younger at diagnosis than women (62.6 years [p25-p75: 49.8–73.9] vs. 71.1 years [p25-p75: 59.7–80.6]). Patients with HCM had more comorbidities than matched controls. The median time of follow-up was 4.4 years (p25-p75: 2.3, 6.7). For HCM patients and matched controls, 1-year, 5-year and 10-year probabilities of death were 10% (95% CI 9–12%), 28% (95% CI 26–30%) and 47% (95% CI 42–51%) and 2% (95% CI 1–3%), 13% (95% CI 12–14%) and 24% (95% CI 23–25%) respectively (Figure 1). After adjusting for comorbidities and medications a diagnosis of HCM was associated to a 107% increased risk of death (hazard ratio 2.07 [95% confidence interval 1.60, 2.68], p<0.0001).

Figure 1

Conclusion

In a Danish nationwide cohort, HCM was associated with a significantly higher risk of death compared with the background population. This study emphasizes the importance of continued, life-long follow-up of patients with HCM with the aim to anticipate and treat preventable adverse events. Furthermore, the findings stress the need to develop effective disease-modifying treatment strategies.

Multiple cytokines for the detection of Mycobacterium tuberculosis infection in children with tuberculosis

SETTING

Interferon-gamma (IFN-γ) release assays (IGRAs) play an important role in the diagnosis of Mycobacterium tuberculosis infection. However, in children with tuberculosis (TB), some studies have shown increased frequencies of false-negative or indeterminate IGRA results.

OBJECTIVE

To analyse the spectrum of different cytokines to improve the diagnostic accuracy of IGRAs in latent tuberculous infection (LTBI) and active TB.

DESIGN

We performed multiplex cytokine expression analysis of QuantiFERON® Gold In-Tube supernatants in children with active TB (n = 21) and disease-free contacts with (n = 15) and without LTBI (n = 12), to determine the sensitivity and specificity of the modified tests.

RESULTS

Of 21 initial cytokines analysed, IFN-γ and six other candidates (interleukin [IL] 2, inducible protein 10 [IP-10], IL-13, IL-1α, tumour necrosis factor alpha [TNF-α] and granulocyte-macrophage colony-stimulating factor [GM-CSF]) were significantly more elevated in children with TB and those with LTBI than in the non-infected controls. Sensitivity and specificity were similar for IFN-γ and IL-2, but lower for the remaining candidates. Notably, a subset of candidates, including IP-10, showed M. tuberculosis antigen-induced specific expression in non-infected children. None of the candidates showed differences in expression between children with TB and those with LTBI.

CONCLUSIONS

Our results did not suggest that alternative IGRA cytokines can distinguish between children with active TB and those with LTBI. IFN-γ and IL-2 showed comparable capacity in diagnosing M. tuberculosis infection in our study groups.

Deconfounding Microarray Analysis

Objectives: Microarray analysis requires standardized specimens and evaluation procedures to achieve acceptable results. A major limitation of this method is caused by heterogeneity in the cellular composition of tissue specimens, which frequently confounds data analysis. We introduce a linear model to deconfound gene expression data from tissue heterogeneity for genes exclusively expressed by a single cell type.

Methods: Gene expression data are deconfounded from tissue heterogeneity effects by analyzing them using an appropriate linear regression model. In our illustrating data set tissue heterogeneity is being measured using flow cytometry. Gene expression data are determined in parallel by real time quantitative polymerase chain reaction (qPCR) and microarray analyses. Verification of deconfounding is enabled using protein quantification for the respective marker genes.

Results: For our illustrating dataset, quantification of cell type proportions for peripheral blood mononuclear cells (PBMC) from tuberculosis patients and controls revealed differences in B cell and monocyte proportions between both study groups, and thus heterogeneity for the tissue under investigation. Gene expression analyses reflected these differences in celltype distribution. Fitting an appropriate linear model allowed us to deconfound measured transcriptome levels from tissue heterogeneity effects. In the case of monocytes, additional differential expression on the single cell level could be proposed. Protein quantification verified these deconfounded results.

Conclusions: Deconfounding of transcriptome analyses for cellular heterogeneity greatly improves interpretability, and hence the validity of transcriptome profiling results.

Sample Selection for Microarray Gene Expression Studies

Objectives: The choice of biomedical samples for microarray gene expression studies is decisive for both validity and interpretability of results. We present a consistent, comprehensive framework to deal with the typical selection problems in microarray studies.

Methods: Microarray studies are designed either as case-control studies or as comparisons of parallel groups from cohort studies, since high levels of random variation in the experimental approach thwart absolute measurements of gene expression levels. Validity and results of gene expression studies heavily rely on the appropriate choice of these study groups. Therefore, the so-called principles of comparability, which are well known from both clinical and epidemiological studies, need to be applied to microarray experiments.

Results: The principles of comparability are the study-base principle, the principle of deconfounding and the principle of comparable accuracy in measurements. We explain each of these principles, show how they apply to microarray experiments, and illustrate them with examples. The examples are chosen as to represent typical stumbling blocks of microarray experimental design, and to exemplify the benefits of implementing the principles of comparability in the setting of micro-array experiments.

Conclusions: Microarray studies are closely related to classical study designs and therefore have to obey the same principles of comparability as these. Their validity should not be compromised by selection, confounding or information bias. The so-called study-base principle, calling for comparability and thorough definition of the compared cell populations, is the key principle for the choice of biomedical samples and controls in microarray studies.

Erratum: "A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow" [Biomicrofluidics , 064101 (2016)]

[This corrects the article DOI: 10.1063/1.4964813.].

Testis specific histone 2B is associated with sperm chromatin dynamics and bull fertility-a pilot study

BACKGROUND

Bull fertility is the degree of sperm's ability to fertilize and activate the egg and support embryo development, and this is critical for herd reproductive performance. We used the bull as a unique model organism for the study of male fertility because cattle genetics and physiology is similar to those of other mammals including humans. Moreover, reliable fertility data along with well-established in vitro systems are available for bovine. The objective of this original study was to ascertain evolutionary diversification and expression dynamics of Testis Specific Histone 2B (TH2B) in sperm from Holstein bulls with different fertility scores.

METHODS

The intensity of TH2B was determined by using flow cytometry in sperm from 13 high and 13 low fertility bulls. Expression levels of TH2B were measured using immunofluorescence and Western blotting in sperm from five high and five low fertility bulls. Sequence identity, evolutionary distance and interactome of TH2B were evaluated by dotmatcher, STRING and Cytoscape. Data were analyzed using linear mixed effects model and regression plots were drawn.

RESULTS

The intensity of TH2B as measured by flow cytometry was significantly affected by an interaction between fertility group and fertility score (P = 0.0182). The intensity of TH2B in sperm from the high fertility group decreased (P = 0.0055) as fertility increased. TH2B was constantly detectable in sperm and expression levels of TH2B decreased in relation to fertility in sperm from the high fertility group (P = 0.018). TH2B biological functions include male gamete generation, chromosome organization, DNA packaging, DNA conformation change, chromatin organization, nucleosome organization, chromatin disassembly, spermatid nucleus elongation, spermatid nucleus differentiation, sperm motility, chromatin organization, chromatin condensation, chromatin silencing, nucleus organization, and chromatin remodeling (P < 0.05).

CONCLUSIONS

We elucidated the cellular localization and molecular physiology of TH2B using both computational and cell biology approaches. In addition to advancing the fundamental science of mammalian male gamete, the present findings can be potentially used to evaluate semen quality and predict male fertility in the future.

TRIAL REGISTRATION

This study did not involve any live animals. We did not perform any anesthesia, euthanasia, or any kind of animal sacrifice. The cryopreserved semen samples were obtained from Alta Genetics, Inc., Watertown, WI, USA. All samples were preserved in liquid nitrogen.

A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow

The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and testing novel interventions in diseased tissue.

CT, MR Imaging and Angiography in Pancreatic Apudomas

Findings at CT, MR imaging and angiography in 29 patients with pancreatic apudomas are presented. CT and angiography were performed in all the patients, MR imaging in 10. Twenty-five patients underwent laparotomy. The ability of the different imaging methods to localize the primary tumor and detect hepatic metastases was compared. CT and MR imaging depicted the primary tumor in 79% and 88% of the cases respectively, angiography in 72%. Enhancement patterns at CT and signal intensity variations at MR imaging were unspecific parameters regarding different types of tumors. CT and MR imaging were considerably more accurate than angiography in evaluating local tumor resectability. Angiography revealed more numerous small hepatic metastases (<0.5 cm) than CT or MR imaging, but missed metastases in the left lobe in 5 patients. MR imaging seems promising in localizing and characterizing pancreatic apudomas, but further evaluation is needed before any conclusion can be drawn. At present dynamic incremental CT seems mandatory in the evaluation of pancreatic apudomas. Angiography is of value for preoperative and preembolization vascular mapping, and in localizing small pancreatic apudomas not shown at CT or MR imaging. Faster dynamic thin slice CT scanning and fast-sequence MR imaging may increase the sensitivity of detecting small primary pancreatic apudomas.

Spontaneous Pathology and Routine Clinical Pathology Parameters in Aging Beagle Dogs

AstraZeneca ran a bespoke study to generate age-matched clinical pathology and histopathology data from a cohort of Beagle dogs aged between 25 and 37 months to support the use of these older animals in routine preclinical toxicology studies. As the upper age range of Beagle dogs routinely used in toxicology studies does not normally exceed 24 months, there is an absence of appropriate age-matched historical control data. The generation of such data was crucial to understand whether age-related differences in spontaneous findings might confound the interpretation of toxicology study data. While the majority of the histopathology findings in all the older dogs occurred at a similar prevalence as those expected in young adult dogs (<24 months), a number of differences were observed in the thymus (involution), bone marrow (increased adiposity), testes (degenerative changes), and lung (fibrosis, pigment and alveolar hyperplasia) that could be misinterpreted as a test article effect. Minor differences in some clinical pathology values (hemoglobin, alkaline phosphatase, absolute reticulocytes) were of a small magnitude and considered unlikely to affect the interpretation of study data.

Infektionen

Die Meldung und Erfassung von Infektionskrankheiten ist in Deutschland durch das Infektionsschutzgesetz (IfSG) geregelt. In §6 sind meldepflichtige Krankheiten nach gewissen Vorgaben geregelt.

Interferon-alpha-2b alone and combined with octreotide in primary carcinoid cell-cultures

Interferon and octreotide are two main therapeutic options in metastatic carcinoid disease. In primary cell cultures prepared from 26 previously untreated carcinoid patients interferon-alpha 2b (alpha-INF), alone and combined with octreotide, significantly reduced medium serotonin (5-HT). The amines were measured with reversed phase HPLC and electrochemical detection, total DNA with a photometric method. Interferon lowered the medium concentration of serotonin to 53% (range 42-79%), octreotide alone to 44% (range 23-48%). Neither interferon, octreotide nor the combined treatment decreased DNA content. Octreotide had no effect on intracellular 5-HT. Both interferon alone and combined with octreotide lowered intracellular 5-HT concentrations significantly. This may represent a direct biochemical effect of interferon on tryptophan metabolism.

Is the operative delivery rate in low-risk women dependent on the level of birth care? A randomised controlled trial

Objective

To investigate possible differences in operative delivery rate among low-risk women, randomised to an alongside midwifery-led unit or to standard obstetric units within the same hospital.

Design

Randomised controlled trial.

Setting

Department of Obstetrics and Gynaecology, Østfold Hospital Trust, Tromsø, Norway.

Population

A total of 1111 women assessed to be at low risk at onset of spontaneous labour.

Methods

Randomisation into one of three birth units: the special unit; the normal unit; or the midwife-led unit.

Main outcome measures

Total operative delivery rate, augmentation, pain relief, postpartum haemorrhage, sphincter injuries and intrapartum transfer, Apgar score <7 at 5 minutes, metabolic acidosis and transfer to neonatal intensive care unit.

Results

There were no significant differences in total operative deliveries between the three units: 16.3% in the midwife-led unit; 18.0% in the normal unit; and 18.8% in the special unit. There were no significant differences in postpartum haemorrhage, sphincter injuries or in neonatal outcomes. There were statistically significant differences in augmentation (midwife-led unit versus normal unit RR 0.73, 95% CI 0.59–0.89; midwife-led unit versus special unit RR 0.69, 95% CI 0.56–0.86), in epidural analgesia (midwife-led unit versus normal unit RR 0.68, 95% CI 0.52–0.90; midwife-led unit versus special unit RR 0.64, 95% CI 0.47–0.86) and in acupuncture (midwife-led unit versus normal unit RR 1.45, 95% CI 1.25–1.69; midwife-led unit versus special unit RR 1.45, 95% CI 1.22–1.73).

Conclusions

The level of birth care does not significantly affect the rate of operative deliveries in low-risk women without any expressed preference for level of birth care.

Histopathologic Features, Immunophenotyping, Clonality, and Eubacterial Fluorescence In Situ Hybridization in Cats With Lymphocytic Cholangitis/Cholangiohepatitis

Feline lymphocytic cholangitis is a poorly characterized disease complex with respect to histologic lesions, immunophenotype, and etiopathogenesis. Seventy-eight cases of feline lymphocytic cholangitis ( n = 51) and feline hepatic lymphoma ( n = 27) were reviewed using standardized histopathology, immunophenotyping (B cell and T cell), polymerase chain reaction for T-cell receptor (TCR) gene rearrangement, and fluorescence in situ hybridization (FISH) for eubacteria. Five histopathologic features in cases of lymphocytic cholangitis assisted in its differentiation from hepatic lymphoma: bile duct targeting ( n = 32, 62.7%), ductopenia ( n = 9, 17.6%), peribiliary fibrosis ( n = 37, 72.5%), portal B-cell aggregates ( n = 36, 70.6%), and portal lipogranulomas ( n = 38, 74.5%). The majority of lymphocytic cholangitis cases ( n = 35, 68.6%) were T cell predominant; 15 (29.4%) had an equal mix of B cells and T cells, and 1 (1.9%) had a B cell–predominant infiltrate; 66.6% of hepatic lymphoma cases were T-cell lymphomas. TCR clonality results were unexpected, with 17.1% of cases of lymphocytic cholangitis having clonal or oligoclonal populations and with T-cell lymphomas having variable TCR clonality (63.6% clonal or oligoclonal, 36.3% polyclonal). The majority of lymphocytic cholangitis ( n = 32 of 36, 88.8%) and all hepatic lymphoma cases had no detectable eubacteria using FISH. As demonstrated here, bile duct targeting, ductopenia, peribiliary fibrosis, portal B-cell aggregates, and portal lipogranulomas are lymphocytic cholangitis features that, along with polyclonal TCR (83%), help differentiate it from hepatic lymphoma. No strong evidence was found implicating in situ bacterial colonization as an etiopathogenesis of lymphocytic cholangitis.

Can conjunctival provocation test facilitate the diagnosis of food allergy in children?

BACKGROUND

Food allergy is common in children, occurring in 5-7.5%. The diagnosis may, however, be difficult. Elevated IgE or positive skin prick test to a food allergen is often considered proof of allergy, but may represent sensitisation without clinical manifestations. For a precise diagnosis oral challenge is necessary, but this is often not performed because of risk of serious allergic reactions. The aim of this study was to evaluate whether conjunctival provocation test would facilitate the diagnosis of IgE-mediated food allergy.

METHODS

One hundred and forty-nine children with 174 possible diagnoses of food allergy were included. General examination, skin prick test and specific IgE were performed, as well as conjunctival provocation test of the suspected food allergen. Open food challenges and double-blind placebo controlled tests were performed in order to diagnose possible food allergy.

RESULTS

Forty-six children with strongly positive conjunctival reactions (rubor, itching, oedema) to fifty food allergens were all proven to have allergy to the food in question. The children with negative conjunctival provocation tests showed no allergic reactions when challenged.

CONCLUSIONS

We find that a strongly positive conjunctival reaction to a food allergen correlates well with true allergy. An oral challenge should be carefully performed. With a negative conjunctival test an oral challenge may safely be performed.

Suppressor of cytokine signaling-3 is affected in T-cells from tuberculosisTB patients

T-cells and T-cell-derived cytokines are crucial mediators of protection against Mycobacterium tuberculosis infection, but these factors are insufficient as biomarkers for disease susceptibility. In order to define T-cell molecules involved in tuberculosis (TB), we compared gene expression profiles of T-cells from patients with active TB, healthy donors with latent M. tuberculosis infection (LTBIs) and non-infected healthy donors (NIDs) by microarray analysis. Pathway-focused analyses identified a prevalent subset of candidate genes involved in the Janus kinase (JAK)-signal transducer and activator of transcription signalling pathway, including those encoding suppressor of cytokine signalling (SOCS) molecules, in the subset of protection-associated genes. Differential expression was verified by quantitative PCR analysis for the cytokine-inducible SH2-containing protein (CISH), SOCS3, JAK3, interleukin-2 receptor α-chain (IL2RA), and the proto-oncogene serine/threonine protein kinase (PIM1). Classification analyses revealed that this set of molecules was able to discriminate efficiently between T-cells from TB patients and those from LTBIs, and, notably, to achieve optimal discrimination between LTBIs and NIDs. Further characterization by quantitative PCR revealed highly variable candidate gene expression in CD4(+) and CD8(+) T-cells from TB patients and only minor differences between CD4(+) and CD8(+) T-cell subpopulations. These results point to a role of cytokine receptor signalling regulation in T-cells in susceptibility to TB.

Atopic dermatitis in premature and term children

OBJECTIVE

To investigate the prevalence of atopic dermatitis (AD) in premature compared with term children, the frequency of food allergy in children with AD, and the possible differences in prevalence of AD in children delivered by caesarean section compared with vaginally delivered children.

DESIGN

Prospective follow-up study over 2 years.

METHOD

609 children (193 premature and 416 term) were included. At 2 years, 512 children (161 premature and 351 term) participated. Children with symptoms consistent with AD/possible food allergy were examined, and the dermatitis was evaluated according to the SCORAD index. Skin prick test, specific IgE, elimination/challenge and DBPC challenge were performed.

RESULTS

18.6% (95/512) of the children (19.9% (32/161) premature and 17.9% (63/351) term) had a diagnosis of AD. The prevalence of adverse reactions to food in all the children with AD was 15.8% (15/95) (similar in preterm and term children). AD was found in 17.5% (30/171) of children delivered by caesarean section, and 19.1% (65/341) delivered vaginally

CONCLUSIONS

The prevalence of AD in the first 2 years of life was 18.6%, with no significant difference between preterm and term children. Adverse reactions to food were found in 15.8% (a similar prevalence in premature and term children). Mode of delivery did not affect prevalence of AD.

Decision-making needs of patients with depression: a descriptive study

The study's purpose was to explore the decision-making needs of patients considering treatment options for their depression. Semi-structured interviews were guided by the Ottawa Decision Support Framework. Of 94 participants, 67 were uncertain about their decision. Common decisions identified were whether or not to take medications, attend support groups, undergo electroconvulsive therapy, and location of care. Those feeling certain were more likely to have made a decision (RR 1.37; 95% CI: 1.05, 1.78). However, 40 patients who had 'made a decision' in the recent past were uncertain about their decision. Compared with those who were certain, the uncertain group felt less informed (2.65 vs. 1.64; P < 0.001), less supported (2.63 vs. 1.88; P < 0.001) and less clear about how they valued the benefits and risks of options (2.57 vs. 1.69; P < 0.001). Other influential factors included concerns about confidentiality, distress from depression, embarrassment, panic attacks and lack of energy. Few patients wanted to defer decision making to their physician (n = 8) or family (n = 1). To support decision making, participants identified the need for: discussions with their psychiatrist, nurse or family doctor; access to printed information; and information provided by health professionals and health societies.

Chromosome aberrations in Norwegian reindeer calves exposed to fallout from the Chernobyl accident

Chromosome aberrations were analysed in 1222 peripheral blood lymphocytes from 24 reindeer, Rangifer tarandus L., calves from central Norway, where considerable fallout from Chernobyl accident had occurred, and in 1532 lymphocytes from 26 calves from three different districts in Northern Norway which were not affected by fallout from the accident. Three dicentrics, two rings, and three translocations were detected in calves from the exposed area, while no dicentrics, nor rings and only one translocation were detected in the control calves. The frequency of chromatid-type aberrations and chromosome deletions did not significantly differ between the two groups. Although the present study is based on a limited number of observations, the radioactive burden in the exposed reindeer, and the differing character of the chromosome aberrations in the two groups, might indicate that certain genetic effects have occurred as a result of the Chernobyl accident in Norwegian reindeer in the most contaminated areas.

Deconfounding microarray analysis - independent measurements of cell type proportions used in a regression model to resolve tissue heterogeneity bias

OBJECTIVES

Microarray analysis requires standardized specimens and evaluation procedures to achieve acceptable results. A major limitation of this method is caused by heterogeneity in the cellular composition of tissue specimens, which frequently confounds data analysis. We introduce a linear model to deconfound gene expression data from tissue heterogeneity for genes exclusively expressed by a single cell type.

METHODS

Gene expression data are deconfounded from tissue heterogeneity effects by analyzing them using an appropriate linear regression model. In our illustrating data set tissue heterogeneity is being measured using flow cytometry. Gene expression data are determined in parallel by real time quantitative polymerase chain reaction (qPCR) and microarray analyses. Verification of deconfounding is enabled using protein quantification for the respective marker genes.

RESULTS

For our illustrating dataset, quantification of cell type proportions for peripheral blood mononuclear cells (PBMC) from tuberculosis patients and controls revealed differences in B cell and monocyte proportions between both study groups, and thus heterogeneity for the tissue under investigation. Gene expression analyses reflected these differences in celltype distribution. Fitting an appropriate linear model allowed us to deconfound measured transcriptome levels from tissue heterogeneity effects. In the case of monocytes, additional differential expression on the single cell level could be proposed. Protein quantification verified these deconfounded results.

CONCLUSIONS

Deconfounding of transcriptome analyses for cellular heterogeneity greatly improves interpretability, and hence the validity of transcriptome profiling results.

Outcome of four weeks' intervention with probiotics on symptoms and endoscopic appearance after surgical reconstruction with a J-configurated ileal-pouch-anal-anastomosis in ulcerative colitis

OBJECTIVE

Pouchitis is a common and troublesome condition in patients operated on with ileal-pouch-anal-anastomosis (IPAA). A disturbed microecology in the pouch has been suggested as one possible explanation. In a previous double-blind, randomized, controlled study we demonstrated clinical improvement of symptoms in patients with ulcerative colitis (UC) operated on with IPAA, during intervention with live probiotic microbes Lactobacilli and Bifidobacteriae. The aim of the present study was to confirm our previous results in a much larger material, including clinical symptoms, faecal flora and endoscopic evaluation, and to compare the results in UC/IPAA patients with those of patients with familial adenomatous polyposis (FAP) with IPAA and UC patients with ileorectal anastomosis (IRA).

MATERIAL AND METHODS

Five hundred millilitres of a fermented milk product (Cultura) containing live lactobacilli (La-5) and bifidobacteriae (Bb-12) was given daily for 4 weeks to 51 UC patients and 10 patients with FAP, operated on with IPAA, and six UC patients operated on for IRA. Stool samples were cultured for examination of lactobacilli, bifidobacteriae, fungi and pH before, during and after intervention. Before, during and after intervention, endoscopic evaluation was performed. Categorized symptomatology was examined prospectively using diary cards in addition to an interview, before and on the last day of intervention.

RESULTS

The number of lactobacilli and bifidobacteriae increased significantly during intervention in the UC patients operated on with IPAA and remained significantly increased one week after intervention. Involuntary defecation, leakage, abdominal cramps and the need for napkins (category I), faecal number and consistency (category II) and mucus and urge to evacuate stools (category III) were significantly decreased during intervention in the UC/IPAA group. In the FAP group there was a significant decrease in faecal leakage, abdominal cramps and use of napkins (category I) during intervention. The median endoscopic score of inflammation was significantly decreased during intervention in the UC/IPAA patients. Blood tests, faecal fungi and faecal pH did not change significantly during intervention.

CONCLUSIONS

Results of this extended study, showing an effect of probiotics on symptoms and endoscopic inflammation in UC patients operated on with IPAA confirm our previously reported effect of probiotics on clinical symptoms and endoscopic score in a smaller, double-blind, randomized, controlled study. The significantly higher response to probiotics in families with increased risk of IBD will have to be repeated in future studies.

Sample selection for microarray gene expression studies

OBJECTIVES

The choice of biomedical samples for microarray gene expression studies is decisive for both validity and interpretability of results. We present a consistent, comprehensive framework to deal with the typical selection problems in microarray studies.

METHODS

Microarray studies are designed either as case-control studies or as comparisons of parallel groups from cohort studies, since high levels of random variation in the experimental approach thwart absolute measurements of gene expression levels. Validity and results of gene expression studies heavily rely on the appropriate choice of these study groups. Therefore, the so-called principles of comparability, which are well known from both clinical and epidemiological studies, need to be applied to microarray experiments.

RESULTS

The principles of comparability are the study-base principle, the principle of deconfounding and the principle of comparable accuracy in measurements. We explain each of these principles, show how they apply to microarray experiments, and illustrate them with examples. The examples are chosen as to represent typical stumbling blocks of microarray experimental design, and to exemplify the benefits of implementing the principles of comparability in the setting of microarray experiments.

CONCLUSIONS

Microarray studies are closely related to classical study designs and therefore have to obey the same principles of comparability as these. Their validity should not be compromised by selection, confounding or information bias. The so-called study-base principle, calling for comparability and thorough definition of the compared cell populations, is the key principle for the choice of biomedical samples and controls in microarray studies.

Testosterone modulates K(+)ATP channels in Sertoli cell membrane via the PLC-PIP2 pathway

Testosterone at physiological intratesticular concentrations induces a dose-dependent depolarisation and an increase in input resistance together with an increment of 45Ca2+ uptake in the Sertoli cells from seminiferous tubules of immature rat. Previous studies have implicated K(+)ATP channels in these testosterone actions. This study demonstrates that testosterone and sulphonylureas (glibenclamide and tolbutamide) depolarise the membrane potential, augment resistance and 45Ca2+ uptake in the Sertoli cells of seminiferous tubules from 10-15 day-old rats. These actions were nullified by the presence of the K(+)ATP channel opener diazoxide. The depolarisation was also observed with the impermeant bovine serum albumin-bound testosterone. Testosterone actions were blocked by both pertussis toxin and the phospholipase C (PLC) inhibitor U73122 implying the involvement of PLC - phosphatidylinositol 4-5 bisphosphate (PIP2) hydrolysis via G protein in testosterone actions. Polycations, including spermine and LaCl3, depolarised the membrane potential and increased the resistance. Hyperpolarisation caused by EGTA was reversed by LaCl3 and by the presence of testosterone. This last effect was nullified by the presence of U73122. All of the above results indicate that the action of testosterone on the Sertoli cell membrane is exercised on the K(+)ATP channels through PLC-PIP2 hydrolysis that closes the channel, depolarises the membrane, and stimulates 45Ca2+ uptake.

[Further development of the International Pneumoconiosis Classification--from ILO 1980 to ILO 2000 and to ILO 2000/German Federal Republic version]

The ILO (1980) Classification has been revised during recent years. The new version is now available as the International Classification of Radiographs of Pneumoconioses (Revised edition 2000). The Guidelines booklet is currently available only in English. Those involved felt it was important to maintain continuity with the ILO (1980) edition, in particular to retain the standard radiographs, despite their restricted quality, so as to ensure comparability with earlier national and international data sets. The standard films illustrating pleural abnormalities, and 'u'-shadows, have been modified and reconstituted. The most important changes relate to assessment of film quality, pleural abnormalities, and additional symbols. In Germany, film quality is characterised as "+", "+-", "+--" and "u" according to whether the ability to assess pneumoconiosis is judged to be unimpeachable ("+") to unusable ("u"). If a film is not classified as "+", then written comments regarding defects are required. For "diffuse" pleural thickening, the ILO (2000) edition now requires the presence also of obliteration of the costophrenic angle. This was not required in the earlier (1980) edition and, as previously, is also not stipulated in the German version. A minimum width of 3 mm (previously 0-5 mm), coded "a", is required both for plaques as well as for the margin to the lateral chest wall. Congruence is thus achieved for criteria, which, in German practice, lead to an indication of suspect occupational disease. Plaques on the diaphragm are not considered for measurement of extent; they are only coded as present or absent. If calcification is identified, then this must also be classified and measured as a localised plaque. Extent of calcification on its own, previously coded "0" to "3", is no longer specified. The following new symbols, illustrated by new diagrams, have been introduced: aa = atherosclerotic aorta; at = apical thickening; cg = calcified granuloma (or other non-pneumocononiotic nodules); me = mesothelioma (already previously differentiated from "ca" on the German record sheet); pa = plate atelectasis; pb= parenchymal bands; ra = rounded atelectasis; od = other disease. (Examples of the latter are illustrated diagrammatically by lobar pneumonia, aspergilloma, goiter and hiatal hernia.) Earlier national differences (ILO 1980/German Federal Republic) on particular issues have also been agreed among German "double-readers" ["Zweitbeurteiler"]. However, conformity between the original (ILO 2000) text and the national (German) modified text has been retained in large measure. The detailed descriptions of the standard films differ in certain respects from the German (1980) definitions. Some revision of individual descriptions of the films are proposed. Except for a few differences, agreement was reached here too. The definitive date for the change in Germany is expected to be in early 2004. The standard films are already available now through ILO offices in Geneva or Bonn (addresses in appendix.)

Prevalence and risk factors of adenomyosis at hysterectomy

BACKGROUND

The present study was performed to evaluate the prevalence and possible associated risk factors for adenomyosis.

METHODS

Medical records were retrieved and histo-pathological material re-examined for 549 consecutive women undergoing hysterectomy in a two-year period from 1990-1991.

RESULTS

The prevalence of adenomyosis in the study varied from 10.0-18.2%, depending on different diagnostic criteria. The presence of endometrial hyperplasia at the time of hysterectomy was the only variable significantly associated with adenomyosis (OR = 3.0; 95% CI: 1.2-8.3). No statistically significant association was found between adenomyosis and previous caesarean section, endometrial curettage or evacuation of the uterus. Furthermore, we did not see any significant association between adenomyosis and pain-related symptoms, indication for hysterectomy, age, parity or number of myometrial samples.

CONCLUSIONS

Our study stresses the need for precise diagnostic criteria for adenomyosis, and furthermore indicates that endometrial hyperplasia and adenomyosis may have a common aetiology.

Patterns of cerebrospinal fluid pathology correlate with disease progression in multiple sclerosis

Multiple sclerosis is a chronic inflammatory and demyelinating disease of the CNS with, as yet, an unknown aetiology. Temporal profile, intensity and treatment responses are highly variable in multiple sclerosis suggesting pathogenetic heterogeneity. This hypothesis has been supported by histopathological studies disclosing at least four different subtypes of acute demyelinating lesions. Although stratification of multiple sclerosis patients into these categories would be extremely helpful for clinical studies, this approach is impractical as it requires brain biopsy. In this study we investigated CSF cytology from 60 multiple sclerosis patients by flow cytometry. We identified different patterns of CSF cytology, which were independent of immunological parameters in the peripheral blood. The most variable CSF parameter was the B cell to monocyte ratio, which remained stable during different phases of disease in selected patients. The ratio correlated with disease progression but not with disability or disease duration in a retrospective, consecutive analysis. A high ratio (predominance of B cells) was associated with more rapid disease progression, whereas a low ratio (predominance of monocytes) was found in patients with slower progression. Our study demonstrates the existence and potential clinical relevance of different CSF cytology patterns. We hypothesize that CSF cytology patterns may reflect the heterogeneity in the pathogenesis of multiple sclerosis.

No association of three polymorphisms in the alpha-2-macroglobulin and lipoprotein related receptor genes with multiple sclerosis

Alpha-2-macroglobulin (A2M) is a proteinase inhibitor involved in deactivation of cytokines and modulation of antigen-mediated immune responses. Based on its role in inflammatory and neurodegenerative disorders, we investigated the role of A2M and its receptor low-density lipoprotein receptor-related protein (LRP) for the development of multiple sclerosis (MS). We analyzed the frequency of two polymorphisms in the A2M (Val 1000 Ile, Exon 18 del), and one polymorphism in the LRP (A216V) gene in a case control study involving 326 MS patients, and 290 controls, all defined for the expression of HLA-DR15. No association was found for any of the three polymorphism with MS. Furthermore, no differences in serum A2M levels were detected between MS patients and controls. The results do not suggest a contribution of A2M and LRP to the development of MS.

New approaches to dissect degeneracy and specificity in T cell antigen recognition

The acquired immune system is a complex and very effective defense against invading pathogens such as bacteria and viruses. T cells are central to the acquired immune system by controlling B and T cell activation and induction of T cell effector functions. The key event for T cell activation is the recognition of a specific antigen by the T cell receptor. During the past decade antigen recognition of T cells has been investigated intensively leading to new insights into the molecular mechanisms of T cell activation. In addition to the resolution of the molecular structure of the trimolecular complex (T cell receptor, peptide, major histocompatibility complex) functional studies have demonstrated the flexibility of the T cell receptor interaction with its ligand. These observations have had strong implications for the understanding of T cell selection, maturation, and repertoire maintenance. In addition, the flexibility of the T cell receptor has provided the basis for novel methods to dissect antigen recognition and define the repertoire of ligands for a given receptor. Here, we summarize recent progress on T cell recognition and method innovations with respect to future studies in autoimmune diseases.

NK cells are essential for effective BCG immunotherapy

Adjuvant intravesical bacillus Calmette-Guérin (BCG) therapy is a well-established and successful adjuvant immunotherapy in the treatment of superficial bladder cancer. Although the function of natural killer (NK) cells in other immunotherapeutic regimens (e.g., lymphokine-activated killer [LAK] cell or interleukin-2 [IL-2] therapy) has been established, the contribution of NK cells to effective BCG immunotherapy is not clear. We used a human in vitro system to analyze the role of NK cells in BCG-induced cellular cytotoxicity. After stimulation of mononuclear cells with BCG for 7 days, these BCG-activated killer (BAK) cells displayed substantial cytotoxicity against bladder tumor cells. Magnetic depletion experiments and fluorescence activated cell sorting revealed that NK cells were the major effector cell population. To address NK cell function in vivo, we studied a syngeneic orthotopic murine bladder cancer model and compared BCG immunotherapy in C57BL/6 wild-type mice, NK-deficient beige mice and mice treated with anti-NK1.1 monoclonal antibody. Four weekly instillations of viable BCG significantly prolonged survival in wild-type mice compared with control mice treated with solvent alone. In contrast, BCG therapy was completely ineffective in NK-deficient beige mice and in mice treated with anti-NK1.1 monoclonal antibody. These findings suggest a key role for NK cells during BCG immunotherapy.

Rapid identification of local T cell expansion in inflammatory organ diseases by flow cytometric T cell receptor Vbeta analysis

Oligoclonal expansion of antigen-specific T cells occurs frequently during inflammatory diseases. These cells may persist for a long time at high frequency in the body and be enriched in the affected tissues. As a screening test for expanded cell T cell populations at sites of inflammation, we developed an optimized methodology for flow-cytometry-based quantification of T cell receptor Vbeta (TCRBV) expression. We first validated the specificity of a TCRBV-specific monoclonal antibody set by direct comparison with PCR-based analysis of mono- and polyclonal T cell samples. This monoclonal antibody (mAb) panel recognized approximately two thirds of the T cell receptor alpha/beta repertoire in a group of 64 healthy donors and allowed defining TCR usage in the CD4+ and CD8+ subsets. The reliable detection of expanded Vbeta gene families in T cell populations was confirmed in experiments on superantigen-stimulated T cells. Through differential TCR analysis on T cell subpopulations in cerebrospinal fluid and blood in patients with acute encephalitis, we were able to identify locally expanded CD8+ T cells. The power of this approach affords not only high-throughput comparative TCR analysis for immunological studies in vitro, but also rapid ex vivo identification of cell populations enriched in organ compartments during inflammatory diseases.