Artificial intelligence to predict oncological outcome directly from hematoxylin and eosin-stained slides in urology

INTRODUCTION

Artificial intelligence (AI) has been successfully applied for automatic tumor detection and grading in histopathological image analysis in urologic oncology. The aim of this review was to assess the applicability of these approaches in image-based oncological outcome prediction.

EVIDENCE ACQUISITION

A systematic literature search was conducted using the databases MEDLINE through PubMed and Web of Science up to April 20, 2021. Studies investigating AI approaches to determine the risk of recurrence, metastasis, or survival directly from H&E-stained tissue sections in prostate, renal cell or urothelial carcinoma were included. Characteristics of the AI approach and performance metrics were extracted and summarized. Risk of bias (RoB) was assessed using the PROBAST tool.

EVIDENCE SYNTHESIS

16 studies yielding a total of 6658 patients and reporting on 17 outcome predictions were included. Six studies focused on renal cell, six on prostate and three on urothelial carcinoma while one study investigated renal cell and urothelial carcinoma. Handcrafted feature extraction was used in five, a convolutional neural network (CNN) in six and a deep feature extraction in four studies. One study compared a CNN with handcrafted feature extraction. In seven outcome predictions, a multivariable comparison with clinicopathological parameters was reported. Five of them showed statistically significant hazard ratios for the AI's model's-prediction. However, RoB was high in 15 outcome predictions and unclear in two.

CONCLUSIONS

The included studies are promising but predominantly early pilot studies, therefore primarily highlighting the potential of AI approaches. Additional well-designed studies are needed to assess the actual clinical applicability.

Integration of deep learning-based image analysis and genomic data in cancer pathology: A systematic review

BACKGROUND

Over the past decade, the development of molecular high-throughput methods (omics) increased rapidly and provided new insights for cancer research. In parallel, deep learning approaches revealed the enormous potential for medical image analysis, especially in digital pathology. Combining image and omics data with deep learning tools may enable the discovery of new cancer biomarkers and a more precise prediction of patient prognosis. This systematic review addresses different multimodal fusion methods of convolutional neural network-based image analyses with omics data, focussing on the impact of data combination on the classification performance.

METHODS

PubMed was screened for peer-reviewed articles published in English between January 2015 and June 2021 by two independent researchers. Search terms related to deep learning, digital pathology, omics, and multimodal fusion were combined.

RESULTS

We identified a total of 11 studies meeting the inclusion criteria, namely studies that used convolutional neural networks for haematoxylin and eosin image analysis of patients with cancer in combination with integrated omics data. Publications were categorised according to their endpoints: 7 studies focused on survival analysis and 4 studies on prediction of cancer subtypes, malignancy or microsatellite instability with spatial analysis.

CONCLUSIONS

Image-based classifiers already show high performances in prognostic and predictive cancer diagnostics. The integration of omics data led to improved performance in all studies described here. However, these are very early studies that still require external validation to demonstrate their generalisability and robustness. Further and more comprehensive studies with larger sample sizes are needed to evaluate performance and determine clinical benefits.

Deep learning can predict lymph node status directly from histology in colorectal cancer

BACKGROUND

Lymph node status is a prognostic marker and strongly influences therapeutic decisions in colorectal cancer (CRC).

OBJECTIVES

The objective of the study is to investigate whether image features extracted by a deep learning model from routine histological slides and/or clinical data can be used to predict CRC lymph node metastasis (LNM).

METHODS

Using histological whole slide images (WSIs) of primary tumours of 2431 patients in the DACHS cohort, we trained a convolutional neural network to predict LNM. In parallel, we used clinical data derived from the same cases in logistic regression analyses. Subsequently, the slide-based artificial intelligence predictor (SBAIP) score was included in the regression. WSIs and data from 582 patients of the TCGA cohort were used as the external test set.

RESULTS

On the internal test set, the SBAIP achieved an area under receiver operating characteristic (AUROC) of 71.0%, the clinical classifier achieved an AUROC of 67.0% and a combination of the two classifiers yielded an improvement to 74.1%. Whereas the clinical classifier's performance remained stable on the TCGA set, performance of the SBAIP dropped to an AUROC of 61.2%. Performance of the clinical classifier depended strongly on the T stage.

CONCLUSION

Deep learning-based image analysis may help predict LNM of patients with CRC using routine histological slides. Combination with clinical data such as T stage might be useful. Strategies to increase performance of the SBAIP on external images should be investigated.

Gastrointestinal cancer classification and prognostication from histology using deep learning: Systematic review

BACKGROUND

Gastrointestinal cancers account for approximately 20% of all cancer diagnoses and are responsible for 22.5% of cancer deaths worldwide. Artificial intelligence-based diagnostic support systems, in particular convolutional neural network (CNN)-based image analysis tools, have shown great potential in medical computer vision. In this systematic review, we summarise recent studies reporting CNN-based approaches for digital biomarkers for characterization and prognostication of gastrointestinal cancer pathology.

METHODS

Pubmed and Medline were screened for peer-reviewed papers dealing with CNN-based gastrointestinal cancer analyses from histological slides, published between 2015 and 2020.Seven hundred and ninety titles and abstracts were screened, and 58 full-text articles were assessed for eligibility.

RESULTS

Sixteen publications fulfilled our inclusion criteria dealing with tumor or precursor lesion characterization or prognostic and predictive biomarkers: 14 studies on colorectal or rectal cancer, three studies on gastric cancer and none on esophageal cancer. These studies were categorised according to their end-points: polyp characterization, tumor characterization and patient outcome. Regarding the translation into clinical practice, we identified several studies demonstrating generalization of the classifier with external tests and comparisons with pathologists, but none presenting clinical implementation.

CONCLUSIONS

Results of recent studies on CNN-based image analysis in gastrointestinal cancer pathology are promising, but studies were conducted in observational and retrospective settings. Large-scale trials are needed to assess performance and predict clinical usefulness. Furthermore, large-scale trials are required for approval of CNN-based prediction models as medical devices.

Quantum Critical Point in the Itinerant Ferromagnet Ni_{1-x}Rh_{x}

We report a chemical substitution-induced ferromagnetic quantum critical point in polycrystalline Ni_{1-x}Rh_{x} alloys. Through magnetization and muon spin relaxation measurements, we show that the ferromagnetic ordering temperature is suppressed continuously to zero at x_{crit}=0.375 while the magnetic volume fraction remains 100% up to x_{crit}, pointing to a second order transition. Non-Fermi liquid behavior is observed close to x_{crit}, where the electronic specific heat C_{el}/T diverges logarithmically, while immediately above x_{crit} the volume thermal expansion coefficient α_{V}/T and the Grüneisen ratio Γ=α_{V}/C_{el} both diverge logarithmically in the low temperature limit, further indication of a ferromagnetic quantum critical point in Ni_{1-x}Rh_{x}.

Magnetic and Structural Quantum Phase Transitions in CeCu_{6-x}Au_{x} are Independent

The heavy-fermion compound CeCu_{6-x}Au_{x} has become a model system for unconventional magnetic quantum criticality. For small Au concentrations 0≤x<0.16, the compound undergoes a structural transition from orthorhombic to monoclinic crystal symmetry at a temperature T_{s} with T_{s}→0 for x≈0.15. Antiferromagnetic order sets in close to x≈0.1. To shed light on the interplay between quantum-critical magnetic and structural fluctuations we performed neutron-scattering and thermodynamic measurements on samples with 0≤x≤0.3. The resulting phase diagram shows that the antiferromagnetic and monoclinic phase coexist in a tiny Au concentration range between x≈0.1 and 0.15. The application of hydrostatic and chemical pressure allows us to clearly separate the transitions from each other and to explore a possible effect of the structural transition on the magnetic quantum-critical behavior. Our measurements demonstrate that at low temperatures the unconventional quantum criticality exclusively arises from magnetic fluctuations and is not affected by the monoclinic distortion.

Vascular complication after percutaneous femoral cerclage wire

Cerclage wire is an effective fracture fixation method. However, its mechanical benefits are countered by local ischemia. Its efficacy for treating femoral periprosthetic fractures has been demonstrated since femoral fixation is possible even there is a stem in the diaphysis. It securely holds the proximal femur typically with an additional plate. The development of minimally-invasive surgery with plate fixation has led to the cerclage wire being inserted percutaneously. Here, we report on a case of secondary femoral ischemia following percutaneous cerclage wire of a periprosthetic femoral fracture. This was a Vancouver type B1 fracture. On the 3rd day after admission, minimally-invasive fixation with a femoral locking plate was performed with five cerclage wires added percutaneously. During the immediate postoperative course, the patient developed ischemia of the operated leg that required vascular surgery after confirmation by CT angiography. An arterial stop was visible with deviation of the superior femoral artery, which was not properly surrounded by the cerclage wire. The latter pulled perivascular tissues towards the femur. When combined with reduced arterial elasticity due to severe atherosclerosis, it resulted in arterial plication. The postoperative course was marked by multiple organ failure and death of the patient. Percutaneous surgery is an attractive option but has risks. The presence of severe atherosclerosis is a warning sign for loss of tissue elasticity. This complication can be prevented by preparing the bone surfaces and carefully positioning the patient on the traction table to avoid forced adduction. The surgeon must also be familiar with alternative techniques to cerclage wire such as polyaxial screws and additional plates.

Visual Working Memory Requires Permissive and Instructive NO/cGMP Signaling at Presynapses in the Drosophila Central Brain

The gaseous second messenger nitric oxide (NO) has been shown to regulate memory formation by activating retrograde signaling cascades from post- to presynapse that involve cyclic guanosine monophosphate (cGMP) production to induce synaptic plasticity and transcriptional changes. In this study, we analyzed the role of NO in the formation of a visual working memory that lasts only a few seconds. This memory is encoded in a subset of ring neurons that form the ellipsoid body in the Drosophila brain. Using genetic and pharmacological manipulations, we show that NO signaling is required for cGMP-mediated CREB activation, leading to the expression of competence factors like the synaptic homer protein. Interestingly, this cell-autonomous function can also be fulfilled by hydrogen sulfide (H₂S) through a converging pathway, revealing for the first time that endogenously produced H₂S has a role in memory processes. Notably, the NO synthase is strictly localized to the axonal output branches of the ring neurons, and this localization seems to be necessary for a second, phasic role of NO signaling. We provide evidence for a model where NO modulates the opening of cGMP-regulated cation channels to encode a short-term memory trace. Local production of NO/cGMP in restricted branches of ring neurons seems to represent the engram for objects, and comparing signal levels between individual ring neurons is used to orient the fly during search behavior. Due to its short half-life, NO seems to be a uniquely suited second messenger to encode working memories that have to be restricted in their duration.

The visual orientation memory of Drosophila requires Foraging (PKG) upstream of Ignorant (RSK2) in ring neurons of the central complex

Orientation and navigation in a complex environment requires path planning and recall to exert goal-driven behavior. Walking Drosophila flies possess a visual orientation memory for attractive targets which is localized in the central complex of the adult brain. Here we show that this type of working memory requires the cGMP-dependent protein kinase encoded by the foraging gene in just one type of ellipsoid-body ring neurons. Moreover, genetic and epistatic interaction studies provide evidence that Foraging functions upstream of the Ignorant Ribosomal-S6 Kinase 2, thus revealing a novel neuronal signaling pathway necessary for this type of memory in Drosophila.

Female-enriched and thermosensitive expression of steroidogenic factor-1 during gonadal differentiation in Pleurodeles waltl

In the urodele amphibian Pleurodeles waltl, sex differentiation is genetically controlled, that is, ZZ male vs ZW female, but may be influenced by temperature, which induces a female-to-male sex reversal. We investigated whether steroidogenic factor 1 (SF-1) could be involved in Pleurodeles sex differentiation or in temperature-dependent sex reversal by cloning a Pleurodeles SF-1 cDNA and examining its developmental expression. The 468-amino-acid deduced protein is highly conserved in comparison with other species. In ZZ and ZW control larvae, SF-1 mRNA is detected at the first stage of the thermosensitive period (TSP) in the gonad-mesonephros-interrenal complex (GMI). By the end of TSP at stage 55, SF-1 is expressed in the gonad (Gd) and in the mesonephros-interrenal (MI) both in ZZ and ZW larvae. During this stage, a transient, ZW-specific increase of SF-1 transcription occurs not only in Gd but also in MI, this increase starting earlier in Gd than in MI. Therefore, in P. waltl, an SF-1 upregulation occurs after the onset of the ovarian-specific increase of aromatase mRNA expression. At the end of metamorphosis, the SF-1 transcription level in Gd and MI is nearly the same in both ZZ and ZW larvae. Besides, after long-term heat treatment leading to sex reversal, SF-1 mRNA upregulation is not observed in ZW larvae, in either Gd or MI. However, SF-1 expression is not decreased after a 48-h heat shock applied at the end of the TSP, suggesting that temperature has no inhibitory effect by itself in long-term heat treatment. Estradiol benzoate treatments show that, at the end of the TSP, SF-1 gene transcription could be controlled by the estrogen level. This is in accordance with the female-enriched SF-1 expression and the decreased SF-1 expression following long-term, sex-reversing heat treatment, which is known to decrease aromatase expression and activity. Thus, it is unlikely that SF-1 is directly involved in Pleurodeles temperature-dependent sex reversal.

[Are there predictors for proliferative retinopathy of prematurity and is supplemental oxygen a useful conservative treatment option?]

BACKGROUND

Especially very immature preterm babies develop retinopathy of prematurity (ROP). This study aims at analysing risk factors for proliferative ROP and realizing the efficiency of supplemental oxygen therapy.

PATIENTS

180 preterm babies with birth weight < or = 1 500 grams were included retrospectively.

METHODS

To determine potential predictors all preterm babies with ROP grade > or = 3 were matched to pairs with similar immature babies with ROP 1 or 2. Additionally we examined the influence of supplemental oxygen therapy on the coagulation rate of high grade retinopathy.

RESULTS

44 % of the preterm babies showed ROP. A longer duration of ventilation (21 vs. 33 days), a longer duration of oxygen supplementation (59 vs. 78 days), relapsing sepsis (10 vs. 19 babies with sepsis > 2 times), a large total volume of transfusions (median: 150 mL vs. 105 mL), chronic lung disease (CLD) (6 vs. 15 babies with oxygen requirements at 36 weeks post-menstrual age), a duration of intubation for more than 28 days (13 vs. 6 babies) and the lack of phototherapy (21 vs. 9 babies) were risk factors associated with ROP > or = 3 using univariate analysis [p < 0.05]. Only the both last criteria correlated with high grade ROP after logistic regression. The supplemental oxygen therapy showed no influence on the coagulation rate of high grade ROP. Possibly this therapy influences the frequency of surgical treatment of amotio- and of putting on a cerclage, but this remains still speculative because of the low case number. We saw no negative effect on the frequency of CLD and on the survival of the babies.

CONCLUSIONS

Especially measures against long duration of intubation could help to prevent high grade ROP. The supplemental oxygen therapy may have a positive effect on course.

Steroids, aromatase and sex differentiation of the newt Pleurodeles waltl

In the newt Pleurodeles waltl, genetic sex determination obeys female heterogamety (female ZW, male ZZ). In this species as in most of non-mammalian vertebrates, steroid hormones play a key role in sexual differentiation of gonads. In that context, male to female sex reversal can be obtained by treatment of ZZ larvae with estradiol. Male to female sex reversal has also been observed following treatment of ZZ larvae with testosterone, a phenomenon that was called the "paradoxical effect". Female to male sex reversal occurs when ZW larvae are reared at 32 degrees C during a thermosensitive period (TSP) that takes place from stage 42 to stage 54 of development. Since steroids play an important part in sex differentiation, we focussed our studies on the estrogen-producing enzyme aromatase during normal sex differentiation as well as in experimentally induced sex reversal situations. Our results based on treatment with non-aromatizable androgens, aromatase activity measurements and aromatase expression studies demonstrate that aromatase (i) is differentially active in ZZ and ZW larvae, (ii) is involved in the paradoxical effect and (iii) might be a target of temperature. Thus, the gene encoding aromatase might be one of the master genes in the process leading to the differentiation of the gonad in Pleurodeles waltl.

Effect of cadmium on gonadogenesis and metamorphosis in Pleurodeles waltl (urodele amphibian)

In the amphibian Pleurodeles waltl, steroid hormones play a key role in sex differentiation. Since cadmium has been reported to block receptors of sex steroid hormones, we analyzed the effects of this heavy metal on Pleurodeles larvae gonadogenesis. At stage 42, larvae die in the presence of 10.9 microM Cd in the rearing tap water, with TL(50) of 46.3 h, but the concentration of 5.5 microM is tolerated for more than 60 days. When used at 5.5 microM cadmium accumulation measured by atomic absorption spectrophotometry (AAS) in total homogenates of larvae at stage 54 (after 77 days of exposure to the heavy metal) reached 58.1 microg/g of dry weight. At stage 54, we did not detect inhibitory effects on gonadogenesis in larvae reared in the presence of 5.5 microM Cd since stage 42. When the exposure to 5.5 microM Cd was lengthened after stage 54, metamorphosis was delayed and could not be completed. When larvae were exposed to 10.9 microM Cd from stage 54, metamorphosis did not occur and gonad development was stopped. Our study demonstrates a lack of a direct effect of cadmium on sex determination-differentiation but a strong inhibitory effect on metamorphosis, which impairs further gonadal development.

Effects of androgens on sex differentiation of the urodele Pleurodeles waltl

In nonmammalian vertebrates, steroids have been hypothesized to induce somatic sex differentiation, since manipulations of the steroidal environment of gonads have led to various degrees of sex reversal. Whereas the critical role of estrogens in ovarian differentiation is well documented, studies on androgens have produced a perplexing variety of results depending upon species variations and nature of androgens used. In this way, testosterone induces masculinization of females in some species but provokes paradoxical feminization of males in many other species such as the urodelan Pleurodeles waltl. In reptiles this phenomenon could be interpreted by conversion of exogenous testosterone to estradiol by aromatase. Treatments of Pleurodeles larvae with nonaromatizable androgens bring support to this hypothesis and suggest a role of androgens in sex differentiation. Dihydrotestosterone (DHT) could not induce the paradoxical feminization of ZZ larvae. In addition, DHT as well as 11beta-hydroxy-androstenedione could drive a functional male differentiation of ZW larvae. Moreover, other 5alpha reduced androgens also induced sex reversal of female larvae. Yet, the 5alpha reductase inhibitor CGP 53133 and antiandrogens such as flutamide or cyproterone acetate did not exert any effect on male sex differentiation of ZZ larvae. Though the precise role of androgens is still unknown, especially for 11-oxygenated androgens, our results suggest an implication in male sex differentiation. In this way, testosterone could play a pivotal role in being metabolized either into other androgens during testis differentiation or into estradiol during ovarian differentiation.

Differential expression of P450 aromatase during gonadal sex differentiation and sex reversal of the newt Pleurodeles waltl

A better understanding of vertebrate sexual differentiation could be provided by a study of models in which genetic sex determination (GSD) of gonads can be reversed by temperature. In the newt Pleurodeles waltl, a P450 aromatase cDNA was isolated from adult gonads, and the nucleotide or deduced amino acid sequences showed a high level of identity with various vertebrate species. In adults, aromatase expression was found in gonads and brain. In developing gonads, the expression was found to fit with the thermo-sensitive period (TSP) and was detected in both ZZ and ZW larvae, as well as in ZW submitted during the whole TSP to a masculinizing temperature. In the latter individuals, in situ hybridization and semi quantitative RT-PCR showed that, at the end of TSP, aromatase expression was at the same level than in normal ZZ larvae and was significantly lower than in normal ZW ones. Furthermore, temperature-induced down regulation did not occur when heating was performed at the end of TSP. Our results confirm the importance of aromatase regulation in female versus male differentiation and demonstrate that a down regulation of aromatase expression is involved in the process of sex reversal.

Flavonoids with epidermal growth factor-receptor tyrosine kinase inhibitory activity stimulate PEPT1-mediated cefixime uptake into human intestinal epithelial cells

We have tested 33 flavonoids, occurring ubiquitously in foods of plant origin, for their ability to alter the transport of the beta-lactam antibiotic cefixime via the H+-coupled intestinal peptide transporter PEPT1 in the human intestinal epithelial cell line Caco-2. Of the flavonoids tested, quercetin, genistein, naringin, diosmin, acacetin, and chrysin increased uptake of [14C]cefixime dose dependently by up to 60%. All other flavonoids were either without effect or decreased the absorption of cefixime. Quercetin was shown to increase the Vmax of cefixime influx without changing the apparent Km for transport. However, the expected concomitant increase in intracellular acidification due to PEPT1-mediated cefixime/H+-cotransport was less pronounced in the presence of quercetin. This suggested that pH regulatory systems such as apical Na+/H+-exchange could be activated by quercetin and maintain the proton-motive driving force for cefixime uptake. Since quercetin and genistein have been shown to inhibit epidermal growth factor (EGF)-receptor tyrosine kinases, we applied tyrphostin 25 to prove whether such an inhibition could explain the stimulatory effects seen on cefixime uptake. It was found that tyrphostin 25 simulated the effects of quercetin by increasing cefixime absorption due to maintenance of the transmembrane pH gradient. In conclusion, our studies show that flavonoids with EGF-receptor tyrosine kinase inhibitory activities enhance the intestinal absorption of the beta-lactam antibiotic cefixime in Caco-2 cells by activation of apical Na+/H+-exchange and a concomitant increase of the driving force for PEPT1.

Challenges in research with incarcerated parents and importance in violence prevention

Incarcerated parents present several risk factors for later violence by their children. This study uses comparison groups and repeated measures to evaluate an inmate parenting program. Subjects are inmates at a county detention center, their children, and primary caregivers. Challenges to program implementation and longitudinal research with inmates were identified, along with recommendations to assist future research and programming. Training material should use illustrated, basic language format. Acceptance and participation by inmates and staff require ongoing outreach and communication. Severed relationships are common and future research on inmates with stable family relationships is recommended. Because of inmate transience, integrating parent training into post-release programming is suggested.

Modular chemistry with aluminum phosphanides: cluster formation of (AlP)n (n=3,6,7), Al4P3, and Al4Li4P6 frameworks

The Al3P3 heterocycle 1 is formed in 94% yield by the reaction of the primary silylphosphane 6a with Me3Al in toluene at 70 degrees C. While 1 crystallizes in an isomerically pure form, in which the six-membered Al3P3 ring prefers the chair conformation and the P-H hydrogen atoms adopt exo positions, it isomerizes in solution to give different diastereomers as shown by 1H and 31P NMR spectroscopy. Intermolecular cyclocondensation of 1 at 110 degrees C in toluene leads, under liberation of methane, to the distorted hexameric-prismatic (AlP)6 cluster 2 in 98% yield. The capability of 1 to function as a building block was further used for the synthesis of the solvent-separated ion pair [Li(thf)2]+ [(Me2Al)4(PR)3]- (3) which was prepared by a one-pot reaction of 1 with nBuLi and Me2AlCl in 15% yield. The structure of 3 was established by an X-ray diffraction analysis. Double deprotonation at phosphorus in 1 with RPLi2 (R = iPr3Si) (molar ratio 1:2), and subsequent transformation of the reaction mixture with Me3Al afforded the novel donor-solvent-free cluster 4 in 62% yield. The latter consists of a rhombododecahedral Al4Li4P6 framework, in which the Li centers are three-coordinate. The reaction of the silylphosphane 6b with the trimethylamine adduct of alane furnishes not only the hexamer (RPAIH)6 (R = (iPrMe2C)-Me2Si) but also the corresponding heptamer 5, which has a nonregular polyhedral (AIP)7 framework and represents the first cluster of this type.

Stimulated acoustic emission: pseudo-Doppler shifts seen during the destruction of nonmoving microbubbles

The purpose of this study was to evaluate the appearance and the characteristics of stimulated acoustic emission (SAE) as an echo contrast-specific color Doppler phenomenon with impact on myocardial contrast echocardiography (MCE). Stationary microbubbles of the new contrast agent SH-U 563A (Schering AG) were embedded within a tissue-mimicking gel material. Harmonic power Doppler imaging (H-PDI), color Doppler and pulse-wave Doppler data were acquired using an HDI-5000 equipped with a phased-array transducer (1.67/3.3 MHz). In color Doppler mode, bubble destruction resulted in random noise like Doppler signals. PW-Doppler revealed short "pseudo-Doppler" shifts with a broadband frequency spectrum. Quantification of SAE events by H-PDI demonstrated an exponential decay of signal intensities over successive frames. A strong linear relationship was found between bubble concentration and the square root of the linearized H-PDI signal for a range of concentrations of more than two orders of magnitude (R = 0.993, p < 0.0001). Intensity of the H-PDI signals correlated well with emission power (R = 0.96, p = 0.0014). SAE results from disintegration of microbubbles and can be demonstrated by all Doppler imaging modalities, including H-PDI. Intensity of SAE signals is influenced by the applied acoustic power and correlates highly with the concentration of microbubbles. Because intensity of SAE signals correlates highly with echo contrast concentrations, analysis of SAE signals might be used for quantitative MCE.

Dietary flavone is a potent apoptosis inducer in human colon carcinoma cells

Flavonoids are polyphenolic compounds that occur ubiquitously in plants. They are discussed to represent cancer preventive food components in a human diet that is rich in fruits and vegetables. To understand the molecular basis of the putative anticancer activity of flavonoids, we investigated whether and how the core structure of the flavones, 2-phenyl-4H-1-benzopyran-4-one (flavone) affects proliferation, differentiation, and apoptosis in HT-29 human colon cancer cells. Moreover, the effects of flavone in transformed epithelial cells were compared with those obtained in nontransformed primary mouse colonocytes. Proliferation, differentiation, and apoptosis in transformed as well as nontransformed colon cells were measured by fluorescence-based techniques. Apoptosis was also determined by changes in membrane permeability, FACScan analysis, and detection of DNA fragmentation. Semiquantitative reverse transcription PCR was performed to assess the effects of flavone on transcript levels. Flavone was found to reduce cell proliferation in HT-29 cells with an EC(50) value of 54.8 +/- 1.3 microM and to potently induce differentiation as well as apoptosis. The flavonoid proved to be a stronger apoptosis inducer than the clinically established antitumor agent camptothecin. The effects of flavone in HT-29 cells were associated with changed mRNA levels of cell-cycle- and apoptosis-related genes including cyclooxygenase-2 (COX-2), nuclear transcription factor kappaB (NF-kappaB), and bcl-X(L). Moreover, flavone, but not camptothecin, displayed a high selectivity for the induction of apoptosis and of growth inhibition only in the transformed colonocytes. In conclusion, the plant polyphenol flavone induces effectively programmed cell death, differentiation, and growth inhibition in transformed colonocytes by acting at the mRNA levels of genes involved in these processes. Because these genes play a crucial role in colon carcinogenesis, flavone may prove to be a potent new cytostatic compound with improved selectivity toward transformed cells.

[Heart failure as a cardiac symptom of sarcoidosis. Successful treatment of heart failure with steroids, digitalis and an angiotensin-1-receptor antagonist in sarcoidosis]

BACKGROUND

Sarcoidosis is a multisystemic disorder that may involve every organ. A symptomatic manifestation of the myocardium is possible, in these cases arrhythmias are the most common symptoms.

CASE REPORT

This case report presents a 26-year-old female with the recurrence of Boeck's sarcoid. Fever, chill and a severe reduction in stress tolerance were the first symptoms. At the time of admission she complained of Grade III dyspnea according to the NYHA classification. The echocardiogram showed a severe impairment of the global and left ventricular function. The left ventricular ejection fraction was reduced to 30% and the Tei index was elevated to 1.0. A specimen taken from a mediastinal tumor confirmed the hypothesis of the recurrence of the sarcoidosis. Myocardial perfusion scintigraphy showed typical lesions for myocardial sarcoidosis. There were signs of an old anteroseptal infarction in the resting ECG without evidence of myocardial ischemia during a stress test. Repeated Holter-ECGs were without signs of severe arrhythmias whereas ventricular late potentials were positive. After the combined therapy with steroids, digitalis and an angiotensin-1 receptor antagonist, mediastinal mass and Tei index were reduced and the ejection fraction moved to 56%. Dyspnoea was classified with Grade II according to the NYHA classification.

CONCLUSION

Treatment of asymptomatic sarcoidosis is still controversial, whereas the treatment of life-threatening sarcoidosis, eye involvement or severe hypercalcemia is accepted. This case report presents the successful treatment of severe heart failure with prednisone, glycosides and an angiotensin-1 receptor antagonist. With this combined therapy an improvement of subjective and objective parameters was possible.

Are microbubbles free flowing tracers through the Myocardium? Comparison of indicator-dilution curves obtained from dye dilution and echo contrast using harmonic power Doppler imaging

BACKGROUND

Harmonic power Doppler imaging (H-PDI) has been introduced into the field of contrast echocardiography as a contrast-specific imaging modality. However, there has been considerable skepticism as to whether H-PDI would be quantifiable, because it depends on the destruction of microbubbles and has more complex signal processing than gray scale imaging. The aim of the present study was to evaluate the relationship between the concentration of microbubbles and the resulting H-PDI signals even under conditions where bubble destruction is most likely. Furthermore, we evaluated whether microbubbles of Levovist freely pass the microcirculation, which is a prerequisite for the assessment of myocardial blood flow.

METHODS AND RESULTS

A strong positive correlation was found between the H-PDI signals and the amount of microbubbles up to the onset of acoustic shadowing (r = 0. 968, P<0.001). Time-intensity curves for H-PDI of air-filled microbubbles were compared with time-concentration curves of indocyanine green (ICG) in both a flow phantom and a working heart setup. The mean transit times (MTTs) through the myocardium of both agents were compared after a bolus injection into the left coronary artery. A close correlation was observed between 1/MTT and flow in both setups (r>0.98, P<0.0001). However, at high flow rates, the MTTs of the microbubbles were slightly, albeit not significantly, faster than those of indocyanine green.

CONCLUSIONS

We conclude that microbubbles fulfill the prerequisites of free flowing tracers through the myocardium. Furthermore, H-PDI technology allows a reliable assessment of time-concentration curves of air-filled microbubbles up to the onset of acoustic shadowing.

M-mode analysis of mitral annulus motion for detection of pseudonormalization of the mitral inflow pattern

Left ventricular (LV) diastolic dysfunction is a frequent cause of heart failure. Doppler echocardiography has become the method of choice for the noninvasive evaluation of LV diastolic dysfunction. However, pseudonormalization of mitral inflow often presents a diagnostic problem in clinical practice. We sought to define the role of mitral annulus motion in this setting. We performed echocardiography in 36 consecutive subjects (age 59 +/- 10 years). Eighteen had recently (within 3 months) been diagnosed with coronary artery disease, 18 had clinical suspicion of coronary artery disease, and 15 had symptoms of heart failure (New York Heart Association class 2.4 +/- 0.5). The amplitude (E(M)) and the slope (slope E) of early diastolic motion of the septal mitral annulus were derived from M-mode analysis. Left heart catheterization was performed for direct measurement of LV end-diastolic pressure. Pseudonormalization defined by an E/A ratio > 1 and a LV end-diastolic pressure > or = 16 mm Hg was found in 9 patients. All patients with pseudonormalization were symptomatic (New York Heart Association class 2.8 +/- 0.5). Patients with and without pseudonormalization did not differ with respect to the E/A ratio (1.29 +/- 0.44 vs 1.16 +/- 0.23, p = NS), deceleration time (182 +/- 38 vs 205 +/- 42 ms, p = NS), and isovolumic relaxation time (88 +/- 24 vs 92 +/- 18 ms, p = NS). In the group with pseudonormalization, a significant reduction of E(M) (3.9 +/- 1.6 vs 5.7 +/- 1.5 mm, p = 0.008) and slope E (24.5 +/- 11.8 vs 43.9 +/- 7.7 mm/s, p <0.001) was detected. Using E(M) <4.3 mm and slope E <35 mm/s as cut points, sensitivity and specificity for the detection of pseudonormalization were 66% and 82% for E(M) and 77% and 87% for slope E, respectively. There was no significant relation between LV end-diastolic pressure as a measure of preload and either E(M) (r = 0.44, p >0.5) or slope E (r = 0.30, p >0.2). Thus, E(M) and slope E may be preload-independent tools for assessing LV diastolic dysfunction in symptomatic patients with a pseudonormal mitral inflow pattern and elevated filling pressures.

Comparative analysis of the effects of flavonoids on proliferation, cytotoxicity, and apoptosis in human colon cancer cell lines

Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Their proposed protective role in tumor development may prevail especially in the intestinal tract due to direct exposure of intestinal epithelia to these dietary ingredients. We have screened more than 30 flavonoids for their effects on cell proliferation and potential cytotoxicity in the human colon cancer cell lines Caco-2, displaying features of small intestinal epithelial cells, and HT-29, resembling colonic crypt cells. In addition, for selected compounds we assessed whether they induce apoptosis by determining caspase-3 activation. Studies on the dose dependent effects of the flavonoids showed antiproliferative activity of all compounds with EC50 values ranging between 39.7 +/- 2.3 microM (baicalein) and 203.6 +/- 15.5 microM (diosmin). In almost all cases, growth inhibition by the flavonoids occurred in the absence of cytotoxicity. There was no obvious structure-activity relationship in the antiproliferative effects either on basis of the subclasses (i.e., isoflavones, flavones, flavonols, flavonones) or with respect to kind or position of substituents within a class. In a subset of experiments we examined the antiproliferative activities of the most potent compound of each flavonoid subgroup in addition in LLC-PK1, a renal tubular cell line, and the human breast cancer cell line MCF-7. Out of four flavonols tested, three displayed almost equal antiproliferative activities in all cell lines but fisetin was less potent in MCF-7 cells. The flavanones bavachinin and flavanone inhibited growth of Caco-2 and HT-29 cells with lower EC50 values than that obtained in LLC-PK1 and MCF-7 cells. The lower susceptibility of LLC-PK1 and MCF-7 cells towards growth arrest was even more pronounced in the case of the flavone baicalein. Half maximal growth-inhibition in LLC-PK1 and MCF-7 required 2.5 and 6.6 fold higher concentrations than that needed in the intestinal cell lines. The flavonoids failed to affect apoptosis in LLC-PK1 and MCF-7, whereas baicalein and myricetin were able to induce apoptosis in HT-29 and Caco-2 cells. In conclusion, flavonoids of the flavone, flavonol, flavanone, and isoflavone classes possess antiproliferative effects in different cancer cell lines. The capability of flavonoids for growth inhibition and induction of apoptosis can not be predicted on the basis of their chemical composition and structure.

[Analysis of mitral annulus excursion with tissue Doppler echocardiography (tissue Doppler echocardiography = TDE). Noninvasive assessment of left ventricular, diastolic dysfunction]

BACKGROUND

Mitral inflow velocity, deceleration time, and isovolumic relaxation time recorded by Doppler echocardiography have been widely used to evaluate left ventricular diastolic function but are affected by age, heart rate, loading conditions, and other factors. The diastolic mitral anulus velocity assessed by tissue Doppler echocardiography (TDE) was suggested to provide additional information about LV relaxation less affected by filling pressures.

AIM OF THE STUDY

This study was designed to assess the clinical utility of mitral anulus velocity in the evaluation of left ventricular diastolic function.

PATIENTS AND METHODS

Three groups of patients with a systolic ejection fraction > 45% were separated: 10 normal volunteers (60 +/- 10 y, CON group), 15 asymptomatic patients with known coronary artery disease (60 +/- 11 y, CAD group) and 15 patients with long-term arterial hypertension and heart failure symptoms (58 +/- 9 y, HYP group). The mitral inflow profile (E, A, E/A) was measured by pulsed Doppler, and the deceleration time (DT) and the isovolumic relaxation period (IVRT) were calculated. Systolic, early, and late diastolic velocities of the septal mitral anulus (ST, ET, AT, ET/AT) were assessed by pulsed TDE. All study subjects had invasive measurements of left ventricular end diastolic filling pressures during left heart catheterization.

RESULTS

In the AH group, ET (6.9 +/- 4.8 cm/s) and ET/AT (0.71 +/- 0.28) were reduced compared to the CON group (11.7 +/- 4.7 cm/s and 1.11 +/- 0.36, p < 0.05, respectively) and the CAD group (8.9 +/- 5.4 cm/s and 0.85 +/- 0.26, respectively, p = ns). The groups did not differ with respect to the mitral E/A ratio, the deceleration time and the isovolumic relaxation time. LVED in the HYP group (16 +/- 8 mm Hg) was elevated compared to the CON group (8 +/- 3, p < 0.05) and the CAD group (12 +/- 6 mm Hg, p = ns). No correlation was found between ET and LVED (r = 0.26). When the combination of mitral E/A ratio > 1 with LVED > or = 15 mm Hg was classified as pseudonormalization, the pseudonormalization could be identified by a peak early diastolic mitral anulus velocity (ET) < 7 cm/s and an ET/AT ratio < 1 with a sensitivity of 77% and a specificity of 88%.

CONCLUSIONS

The early diastolic mitral anulus velocity assessed by TDE (ET) is a preload-independent index of LV relaxation. TDE permits the detection of diastolic dysfunction in patients with a pseudonormal mitral inflow and elevated filling pressures.

Regulation of the high-affinity H+/peptide cotransporter in renal LLC-PK1 cells

Di- and tripeptides and peptide mimetics such as beta-lactam antibiotics are efficiently reabsorbed from the tubular lumen by a high-affinity peptide transporter. We have recently identified and characterized this H+-coupled high-affinity peptide transport system in the porcine proximal tubular cell line LLC-PK1. Here we describe for the first time the regulation of the renal high-affinity peptide cotransporter at the cellular level. Uptake of 5 microM 3H-D-Phe-L-Ala into LLC-PK1 cells was significantly increased by lowering [Ca2+]in and decreased by increasing [Ca2+] in. Moreover, it was shown that the [Ca2+]in effects on peptide transport activity were dependent on Ca2+ entry from the extracellular site (e.g., via a store-regulated capacitative Ca2+ influx). Protein kinase C (PKC) was found to transmit the effects of [Ca2+]in on peptide transport. Although we demonstrate by pHin measurements that the PKC inhibitor staurosporine did decrease the transmembrane H+ gradient and consequently should have reduced the driving force for peptide uptake, the only effect on transport kinetics of 3H-D-Phe-L-Ala observed was a significant decrease in Km from 22.7+/-2.5 microM to 10.2+/-1.9 microM with no change in maximal velocity.

[Intraventricular obstructions in dobutamine stress echocardiography: determinants of their development and clinical sequelae]

Dobutamine stress echocardiography (DSE) leads to strong hypercontraction, tachycardia, and peripheral vasodilatation. In previous studies systolic obstruction of the left ventricular outflow tract (LVOT) was observed as a result of these factors. To evaluate left ventricular function and morphology in patients (pts) with induced systolic LVOT obstruction, we used continuous wave (CW) doppler registrations in combination with quantitative 2-D-echocardiography in 100 pts during routinely performed DSE (5-40 micrograms/kg/min). In addition left ventricular wall thickness was measured. Symptoms were registered using a standardised questionnaire and cardiac arrhythmias were counted over a two minute interval at rest and during the maximal heart rate of each patient. During DSE dynamic flow acceleration with late systolic peak velocity above 2 m/second (s) was considered to represent LVOT obstruction in pts with normal flow profiles in the LVOT before infusion of dobutamine. For invasive studies pts were investigated with femoral catheterisation by the method of Judkins. A greater than 50% stenosis was judged to be significant.

RESULTS

Examinations in 73 pts provided data of sufficient quality for echocardiographic and Doppler sonographic evaluations. 39 pts, 26 men, 13 women, mean age 64 +/- 8 years, developed late systolic flow velocities above 2 m/s and therefore formed the obstructive group (grp A). Grp B consisted of 34 pts, 26 men and 8 women, mean age 66 +/- 10 years, who showed normal time velocity integrals during DSE. In 41 pts invasive data provided information concerning the existence and severity of coronary artery disease. There were no significant differences in the increase of heart rate, the product of maximal systolic blood pressure and maximal heart rate or the percentage of pts, who reached their age corrected submaximal heart rate during DSE. Obstructive pts (group A) showed late systolic dynamic acceleration of systolic flow with a mean maximal speed of 315.4 +/- 139.8 cm/s, which peaked 0.12 +/- 0.04 s after the R-wave. From the velocities we calculated a mean pressure gradient of 47.5 +/- 39.7 mm Hg using the modified Bernoulli equation. Group B patients showed lower and earlier maximal speeds with a mean value of 158.2 +/- 37.6 cm/s, 0.09 +/- 0.04 s after the R-wave, corresponding to a pressure gradient of 10.6 +/- 4.9 mm Hg (p < 0.001). Ejection fractions were higher (p < 0.001) before the test in grp A: 68.2 +/- 8% compared to 55.7 +/- 10.4% in B. This difference increased during peak stress: 74.1 +/- 7.7% compared to 59.5 +/- 12.8%. End diastolic (EDVI) and end systolic volume indexes (ESVI) were lower in grp A (p < 0.001). During DSE, the decrease in ESVI was somewhat stronger for pts in grp A. Left ventricular hypertrophy was more often seen with obstruction. Septal thickness was increased in A: 1.45 +/- 0.34 cm compared to 1.13 +/- 0.27 cm in B (p < 0.001). Left ventricular posterior wall measured 1.03 +/- 0.28 cm in A and 0.83 +/- 0.23 cm in B (p < 0.01). 27 pts in grp B and only 9 in grp A had a history of previous myocardial infarction. Showing no difference at rest, wall motion score indexes raised under DSE in both groups and developed significantly higher scores in grp B at peak stress: 1.30 (1.0-1.90) compared to 1.18 (1.0-1.75) in A. We observed typical chest pain more often in grp B. Unspecific symptoms and arrhythmogenic complications were not statistically different, with the exception of ventricular bigeminy which was more often observed in grp B. A decline in the diastolic blood pressure was observed in pts with very severe obstruction (> 3.5 m/s, p < 0.05). Sensitivity of DSE was 84%, specificity 79%. No significant differences between pts with and without obstruction were observed.

SUMMARY

Intraventricular obstructions during DSE are often observed in pts with normal systolic function at rest and during peak stress, especially in the case of left ventricular hypertrophy. (ABSTRACT TRU

Upper and middle lobe bronchoalveolar lavage to diagnose Pneumocystis carinii pneumonia

Pneumocystis carinii pneumonia (PCP) remains the most common lethal opportunistic pulmonary infection in patients infected with the human immunodeficiency virus (HIV). Although the use of prophylactic inhaled pentamidine has effectively reduced the frequency of primary and recurrent episodes of PCP, the aerosolization of pentamidine may have altered the localization of active PCP, resulting in more upper lobe disease. The distribution of disease may have also affected the diagnostic accuracy of standard bronchoalveolar lavage of the middle lobe, with a reduction in sensitivity from about 90 to 65%. In retrospective surveys of patients from our institution, Steiger and Fahy found that pooled multiple-lobe radiographic site-directed bronchoalveolar lavage resulted in diagnostic sensitivities of 91 and 100%, respectively. We performed a follow-up prospective study of 38 consecutive patients on aerosolized pentamidine in whom we lavaged both the middle lobe and an upper lobe. We found that bilobar lavage including routine lavage of an upper lobe increases the diagnostic sensitivity of bronchoalveolar lavage alone to 95% compared with 65% if lavage is performed only in the middle lobe (p < 0.05). Radiographic studies demonstrate a concordant increase in exclusive or predominant upper lobe disease in patients on aerosolized pentamidine, but our results indicate that PCP is recovered more frequently from the upper lobe regardless of the radiographic appearance. We conclude that all patients on prophylactic inhaled pentamidine should undergo bilobar lavage with the inclusion of an upper lobe in the initial evaluation of possible PCP. The diagnostic sensitivity of 95% makes bilobar bronchoalveolar lavage an acceptable sole initial diagnostic modality without the need for initial transbronchial lung biopsy.