Artificial intelligence analysis of ECG signals to predict arrhythmia recurrence after cryoballoon ablation of atrial fibrillation

Introduction

Cryoballoon-based pulmonary vein isolation (CB) is an effective option for rhythm control in atrial fibrillation (AF). There have been multiple attempts to predict arrhythmia recurrence, but with moderate success.

Purpose

To use artificial intelligence (AI) deep electrocardiogram (ECG) analysis to predict arrythmia recurrence after CB.

Methods

In a single-center study of 250 consecutive pts (58.2±12.6 years, 30% female) treated with CB for AF (05.2017–04.2019), 60% had paroxysmal AF (PAF), 66.5% had hypertension, and 27.2% had a redo CB. Analyses included left atrial volume (LA vol: indexed for BSA and assed by angio-MSCT in 76% and the rest with echo), left ventricle ejection fraction (LVEF) and hypertrophy (LVH: septal/posterior wall thickness ≥11mm in ♂ and ≥10mm in ♀) along with 30s arrhythmia recurrence at 2-yr follow-up. Baseline 500Hz raw 12-lead digital ECG signals were analyzed by means of convolutional neural network (CNN) architecture that was taught to process the 12-channel ECG signal (XML). The transfer learning method of CNN parameters learned on a very large number of coded consecutive training ECG samples (n=1,000) was adopted to analyze current sample of ECG signals.

Results

Arrhythmia recurrence at 2-yrs was 46.0% (n=115). There was gradual increase in predictive performance being the lowest if only baseline clinical data were analyzed and the highest combing all baseline clinical data plus anatomical and functional parameters (Table 1: #1–#3). AI baseline ECG analysis alone offered predictive performance similar to that made upon analysis of all baseline clinical data or joint analysis of LA vol, LVH, and LVEF (Table 1: #4). AI results added substantially to predictive performance of models using baseline clinical data alone (#1 vs #5, p<0.001) and joint analysis of baseline clinical plus LA vol, LVH and LVEF (#3 vs #6, p=0.0130) (Fig. 1).

Conclusions

Prediction of recurrence after CB using raw ECG data with deep AI analysis is feasible. Joint analysis of results of AI of baseline ECG and basic clinical data offers predictive performance similar to that made upon analysis of clinical data including advanced information on LA volume and LVH and function. AI analysis of baseline ECG adds significantly to models aimed at recurrent AF prediction.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): National Institute of Cardiology, Warsaw, Poland

Quantitative immunopeptidomics reveals a tumor stroma-specific target for T cell therapy

T cell receptor (TCR)-based immunotherapy has emerged as a promising therapeutic approach for the treatment of patients with solid cancers. Identifying peptide-human leukocyte antigen (pHLA) complexes highly presented on tumors and rarely expressed on healthy tissue in combination with high-affinity TCRs that when introduced into T cells can redirect T cells to eliminate tumor but not healthy tissue is a key requirement for safe and efficacious TCR-based therapies. To discover promising shared tumor antigens that could be targeted via TCR-based adoptive T cell therapy, we employed population-scale immunopeptidomics using quantitative mass spectrometry across ~1500 tumor and normal tissue samples. We identified an HLA-A*02:01-restricted pan-cancer epitope within the collagen type VI α-3 (COL6A3) gene that is highly presented on tumor stroma across multiple solid cancers due to a tumor-specific alternative splicing event that rarely occurs outside the tumor microenvironment. T cells expressing natural COL6A3-specific TCRs demonstrated only modest activity against cells presenting high copy numbers of COL6A3 pHLAs. One of these TCRs was affinity-enhanced, enabling transduced T cells to specifically eliminate tumors in vivo that expressed similar copy numbers of pHLAs as primary tumor specimens. The enhanced TCR variants exhibited a favorable safety profile with no detectable off-target reactivity, paving the way to initiate clinical trials using COL6A3-specific TCRs to target an array of solid tumors.

The Arguments of the COVID-19 Vaccines Opponents on Facebook in Poland: Textual Analysis Study

Background

Social media allow users to quickly spread information and opinions. Unfortunately, it is often a place of anti-vaxxers activity, who create content that spreads easily. This situation leads to an increase in vaccine hesitancy and may result in outbreaks of infectious diseases. We wanted to find and characterize what negative arguments against the COVID-19 vaccines Facebook users create and how the popularity of the allegations against vaccines changes over time.

Methods

We followed the posts published on Facebook by the biggest Polish media. We have selected the highest commented events related to the registration and introduction of the COVID-19 vaccines. Then, we analyzed user comments related to those events and established the main themes of anti-vaccine comments. Using this list of topics, we categorized 3414 comments and checked the frequency of comments from given categories and their variability over time.

Results

The arguments of vaccine opponents about the COVID-19 vaccines can be divided into 12 categories. Seven of them also apply to other vaccines but five types are COVID-19' specific. Two new arguments say that vaccines were not properly tested or do not exist. The third topic mentions the history of the swine flu vaccine and the following narcolepsy cases. The fourth category suggests that vaccine against COVID-19 existed before the pandemic. The last argument says that no one takes responsibility for the side effects of the vaccine. The frequency of arguments from a given category varies over time. We also noticed that, while the comments were mostly negative, the reactions were positive.

Conclusions

Our codebook of anti-vaccine topics can help public health professionals better understand social media content. Real-time monitoring of social media is important because the popularity of certain arguments on Facebook changes rapidly over time but early recognition of social doubts allows for targeted interventions.

Key messages

Online anti-vaccine comments on the COVID-19 vaccines can be divided into 12 topic categories. The frequency of Facebook comments against COVID-19 vaccines from a given topic category varies over time.

Development of A Novel Tool, The Owl-Sleep Inventory, for the Assessment of Sleep Disorders in Children With Comorbid Psychiatric Illness

BACKGROUND: The high prevalence of sleep disorders in children with psychiatric illness is widely recognized and has a significant impact on families. Ascertainment of sleep disorders remains difficult in a fast-paced clinical setting, owing to the lack of short and efficient assessment tools.

OBJECTIVES: In this study, we tested a one-page parent-response behavioural questionnaire aimed at identifying patients for sleep clinic referral: the OWL-Sleep Inventory (OWL-SI : Godbout and Martello, 2009).

DESIGN/METHODS: The OWL-SI contains 9 questions scored 1 to 3: “never/rarely” (1 point), “sometimes” (2 points), “usually” (3 points), with a subjective cut-off of 16 points. We cross-referenced the OWL-SI against a longer, widely used and validated tool, the Child Sleep Habits Questionnaire (CSHQ: Owens et al., 2000). Medical charts of 408 pediat-ric patients with primary psychiatric diagnosis referred to a specialized sleep clinic were reviewed. Within this group, 261 parents/caregivers had completed both the CSHQ and OWL-SI questionnaires between 2011 and mid-2015. The mean age of patients was 7.13±3.54 years (195 boys, 67 girls) and most were diagnosed with autism spectrum disorder (ASD, 46.6%) or attention deficit hyperactivity disorder (ADHD, 25.6%). Internal consistency of the items for both the CSHQ and the OWL-SI was evaluated as well as the correlation between the two sleep measures.

RESULTS: Total scores for the OWL-SI and the CSHQ were significantly correlated (r=0.623, p<0.001). The CSHQ successfully identified more than 98% of patients later confirmed by a clinician as having sleep disturbance, with a cut-off of 41. ASD and ADHD patients scored positively on the CSHQ (55.25 and 55.60). However, the OWL-SI identified only 53% of patients at a cut-off of 16, with mean scores of 16.17 and 15.25 for patients with ASD and ADHD respectively. When lowered to a cut-off of 11, the questionnaire was efficacious at identifying 95.4% of children needing specialized services referral.

CONCLUSION: Parental response to the novel tool OWL-SI correlated significantly with the CSHQ scores. Following this study, the cut-off for the OWL-SI was lowered to 11in order to commensurate with the widely used CSHQ and the answers “never” and “rarely” are scored separately as 0 and 1, respectively. Further studies assessing prospective validity will permit to determine the optimal cut-off score leading to referral.

The paracaspase MALT1: biological function and potential for therapeutic inhibition

The paracaspase MALT1 has a central role in the activation of lymphocytes and other immune cells including myeloid cells, mast cells and NK cells. MALT1 activity is required not only for the immune response, but also for the development of natural Treg cells that keep the immune response in check. Exaggerated MALT1 activity has been associated with the development of lymphoid malignancies, and recently developed MALT1 inhibitors show promising anti-tumor effects in xenograft models of diffuse large B cell lymphoma. In this review, we provide an overview of the present understanding of MALT1's function, and discuss possibilities for its therapeutic targeting based on recently developed inhibitors and animal models.

Malt1 protease inactivation efficiently dampens immune responses but causes spontaneous autoimmunity

The protease activity of the paracaspase Malt1 has recently gained interest as a drug target for immunomodulation and the treatment of diffuse large B-cell lymphomas. To address the consequences of Malt1 protease inactivation on the immune response in vivo, we generated knock-in mice expressing a catalytically inactive C472A mutant of Malt1 that conserves its scaffold function. Like Malt1-deficient mice, knock-in mice had strong defects in the activation of lymphocytes, NK and dendritic cells, and the development of B1 and marginal zone B cells and were completely protected against the induction of autoimmune encephalomyelitis. Malt1 inactivation also protected the mice from experimental induction of colitis. However, Malt1 knock-in mice but not Malt1-deficient mice spontaneously developed signs of autoimmune gastritis that correlated with an absence of Treg cells, an accumulation of T cells with an activated phenotype and high serum levels of IgE and IgG1. Thus, removal of the enzymatic activity of Malt1 efficiently dampens the immune response, but favors autoimmunity through impaired Treg development, which could be relevant for therapeutic Malt1-targeting strategies.

In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks

Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an (241)Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm(2) thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.

Conditional deletion of ferritin h in mice reduces B and T lymphocyte populations

The immune system and iron availability are intimately linked as appropriate iron supply is needed for cell proliferation, while excess iron, as observed in hemochromatosis, may reduce subsets of lymphocytes. We have tested the effects of a ferritin H gene deletion on lymphocytes. Mx-Cre mediated conditional deletion of ferritin H in bone marrow reduced the number of mature B cells and peripheral T cells in all lymphoid organs. FACS analysis showed an increase in the labile iron pool, enhanced reactive oxygen species formation and mitochondrial depolarization. The findings were confirmed by a B-cell specific deletion using Fth^lox/lox; CD19-Cre mice. Mature B cells were strongly under-represented in bone marrow and spleen of the deleted mice, whereas pre-B and immature B cells were not affected. Bone marrow B cells showed increased proliferation as judged by the number of cells in S and G2/M phase as well as BrdU incorporation. Upon in vitro culture with B-cell activating factor of the tumor necrosis factor family (BAFF), ferritin H-deleted spleen B cells showed lower survival rates than wild type cells. This was partially reversed with iron-chelator deferiprone. The loss of T cells was also confirmed by a T cell-specific deletion in Fth^lox/lox;CD4-Cre mice. Our data show that ferritin H is required for B and T cell survival by actively reducing the labile iron pool. They further suggest that natural B and T cell maturation is influenced by intracellular iron levels and possibly deregulated in iron excess or deprivation.

Toward modeling the bone marrow niche using scaffold-based 3D culture systems

In the bone marrow, specialized microenvironments, called niches, regulate hematopoietic stem cell (HSC) maintenance and function through a complex crosstalk between different cell types. Although in vivo studies have been instrumental to elucidate some of the mechanisms by which niches exert their function, the establishment of an in vitro model that recapitulates the fundamental interactions of the niche components in a controlled setting would be of great benefit. We have previously shown that freshly harvested bone marrow- or adipose tissue-derived cells can be cultured under perfusion within porous scaffolds, allowing the formation of an organized 3D stromal tissue, composed by mesenchymal and endothelial progenitors and able to support hematopoiesis. Here we describe 3D scaffold-based perfusion systems as potential models to reconstruct ex vivo the bone marrow stem cell niche. We discuss how several culture parameters, including scaffold properties, cellular makeup and molecular signals, can be varied and controlled to investigate the role of specific cues in affecting HSC fate. We then provide a perspective of how the system could be exploited to improve stem cell-based therapies and how the model can be extended toward the engineering of other specialized stromal niches.

Hematopoietic stem cells reversibly switch from dormancy to self-renewal during homeostasis and repair

Bone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1+cKit+CD150+CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of the most potent HSCs during homeostasis, they are efficiently activated to self-renew in response to bone marrow injury or G-CSF stimulation. After re-establishment of homeostasis, activated HSCs return to dormancy, suggesting that HSCs are not stochastically entering the cell cycle but reversibly switch from dormancy to self-renewal under conditions of hematopoietic stress.

Telomere dysfunction induces environmental alterations limiting hematopoietic stem cell function and engraftment

Cell-intrinsic checkpoints limit the proliferative capacity of primary cells in response to telomere dysfunction. It is not known, however, whether telomere dysfunction contributes to cell-extrinsic alterations that impair stem cell function and organ homeostasis. Here we show that telomere dysfunction provokes defects of the hematopoietic environment that impair B lymphopoiesis but increase myeloid proliferation in aging telomerase knockout (Terc(-/-)) mice. Moreover, the dysfunctional environment limited the engraftment of transplanted wild-type hematopoietic stem cells (HSCs). Dysfunction of the hematopoietic environment was age dependent and correlated with progressive telomere shortening in bone marrow stromal cells. Telomere dysfunction impaired mesenchymal progenitor cell function, reduced the capacity of bone marrow stromal cells to maintain functional HSCs, and increased the expression of various cytokines, including granulocyte colony-stimulating factor (G-CSF), in the plasma of aging mice. Administration of G-CSF to wild-type mice mimicked some of the defects seen in aging Terc(-/-) mice, including impairment of B lymphopoiesis and HSC engraftment. Conversely, inhibition of G-CSF improved HSC engraftment in aged Terc(-/-) mice. Taken together, these results show that telomere dysfunction induces alterations of the environment that can have implications for organismal aging and cell transplantation therapies.

Dormant and Self-Renewing Hematopoietic Stem Cells and Their Niches

In the mouse, over the last 20 years, a set of cell-surface markers and activities have been identified, enabling the isolation of bone marrow (BM) populations highly enriched in hematopoietic stem cells (HSCs). These HSCs have the ability to generate multiple lineages and are capable of long-term self-renewal activity such that they are able to reconstitute and maintain a functional hematopoietic system after transplantation into lethally irradiated recipients. Using single-cell reconstitution assays, various marker combinations can be used to achieve a functional HSC purity of almost 50%. Here we have used the differential expression of six of these markers (Sca1, c-Kit, CD135, CD48, CD150, and CD34) on lineage-depleted BM to refine cell hierarchies within the HSC population. At the top of the hierarchy, we propose a dormant HSC population (Lin(-)Sca1(+)c-Kit(+) CD48(-)CD150(+)CD34(-)) that gives rise to an active self-renewing CD34(+) HSC population. HSC dormancy, as well as the balance between self-renewal and differentiation activity, is at least, in part, controlled by the stem cell niches individual HSCs are attached to. Here we review the current knowledge about HSC niches and propose that dormant HSCs are located in niches at the endosteum, whereas activated HSCs are in close contact to sinusoids of the BM microvasculature.

Regulation of P53 stability in p53 mutated human and mouse hepatoma cells

The tumor suppressor p53 is frequently mutated in cancer. We have investigated the regulation of P53 in p53 wild type mouse hepatoma cells (line 55.1c), in p53 heterozygeously mutated cells (56.1b) and in p53 defective cells (lines 56.1d, 70.4 and HUH7) under various experimental settings. The basal levels of P53 were low in 55.1c cells, but nuclear accumulation occurred upon UV-irradiation. Similarly, UV-exposure induced stabilization of P53 in the heterozygeously p53 mutated 56.1b hepatoma cells. By contrast, the 3 hepatoma lines, which lack transcriptionally active P53, demonstrated high basal nuclear concentrations of P53 protein and, unexpectedly, showed loss of P53 upon UV-irradiation. Expression of p53 mRNA was also decreased in p53 defective cells after 24 hr post UV-irradiation, which may be linked to induction of apoptosis of the irradiated cells under these conditions. Other stressors like H2O2 also mediated a decrease in P53 concentration in p53 defective cells. This effect occurred at very low concentrations and was already detectable 1-2 hr after exposure of cells. There were no signs of apoptosis of H2O2-exposed cells at this time point and no significant changes in p53 mRNA or MDM2 level. These unexpected findings indicate a new aspect related to regulation of P53 stability in cells with a defect in the tumor suppressor protein.

Global gene expression inHa-ras andB-raf mutated mouse liver tumors

Chemically-induced mouse liver tumors harbor mutations in different oncogenes. About 50% of tumors contain activating mutations in the Ha-ras gene contain and about 20% of tumors show point mutations in the B-raf oncogene. We have investigated the gene expression profiles in tumors of the 2 genotypes by microarray analysis. In total, approximately 500 genes or expressed sequences were aberrantly expressed in tumors relative to normal liver tissue. Around two/thirds of them were significantly altered in both Ha-ras and B-raf mutated liver tumors, and most of the remaining genes showed at least qualitatively comparable changes in both tumor types. Several functional clusters were hypothesized in tumors of the 2 genotypes which involve alterations in a battery of genes encoding enzymes of lipid metabolism. The similarity in the patterns of global gene expression of Ha-ras and B-raf mutated liver tumors suggests that mutational activation of the 2 oncogenes results in activation of a common set of transcriptional regulators.

Rex3 (reduced in expression 3) as a new tumor marker in mouse hepatocarcinogenesis

In a previous microarray expression analysis, Rex3, a gene formerly not linked to tumor formation, was found to be highly overexpressed in both Ctnnb1-(beta-Catenin) and Ha-ras-mutated mouse liver tumors. Subsequent analyses by in situ hybridization and real-time PCR confirmed a general liver tumor-specific overexpression of the gene (up to 400-fold). To investigate the role of Rex3 in liver tumors, hepatoma cells were transfected with FLAG- and Myc-tagged Rex3 expression vectors. Rex3 was shown to be exclusively localized to the cytoplasm, as determined by fluorescence microscopy and Western blotting. However, forced overexpression of Rex3 did not significantly affect proliferation or stress-induced apoptosis of transfected mouse hepatoma cells. Rex3 mRNA was determined in primary hepatocytes in culture by real-time PCR. In primary mouse hepatocytes, expression of Rex3 increased while cells dedifferentiated in culture. This effect was abolished when hepatocytes were maintained in a differentiated state. Furthermore, expression of Rex3 decreased in mouse liver with age of mice and the expression profile was highly correlated to that of the tumor markers alpha-fetoprotein and H19. The findings suggest a role of Rex3 as a marker for hepatocyte differentiation/dedifferentiation processes and tumor formation.

Zonal gene expression in murine liver: lessons from tumors

Gene expression in hepatocytes within the liver lobule is differentially regulated along the portal to central axis; however, the mechanisms governing the processes of zonation within the lobule are unknown. A model for zonal heterogeneity in normal liver is proposed, based on observations of differential expression of genes in liver tumors from mice that harbor activating mutations in either Catnb (which codes for beta-catenin) or Ha-ras. According to the model, the regulatory control consists of two opposing signals, one delivered by endothelial cells of the central veins activating a beta-catenin-dependent pathway (retrograde signal), the other by blood-borne molecules activating Ras-dependent downstream cascades (anterograde signal). In conclusion, gradients of opposing signaling molecules along the portocentral axis determine the pattern of enzymes and other proteins expressed in hepatocytes of the periportal and pericentral domains of the liver lobule.

Human p53 knock-in (hupki) mice do not differ in liver tumor response from their counterparts with murine p53

Mouse models are important tools in toxicologic research. Differences between species in pathways contributing to tumor development, however, raise the question in how far mouse models are valid for human risk assessment. One striking difference relates to the frequency of spontaneous liver cancer which is high in certain mouse strains but rather low in humans. Similarly, mutation frequencies in cancer genes are characteristically different, i.e. P53 mutations are frequent in human but very rare in murine liver tumors, whereas Ras genes are often mutated in mouse liver tumors but hardly ever in human liver cancers. Since P53 has been shown to control oncogenic RAS in human cells, we hypothesized that this function of the tumor suppressor could differ in mouse hepatocytes. To test this hypothesis, we used hupki (human p53 knock-in) mice which carry a partly humanized P53 sequence (P53KI). In this study, we report the results of the first hepatocarcinogenesis experiment with this strain of mice. Mice of the genotypes P53KI/KI, P53WT/KI and P53WT/WT were treated with N-nitrosodiethylamine at 2 weeks of age and killed 35 weeks later. The frequency of liver tumors and glucose-6-phosphatase-altered liver lesions was almost identical in all three P53 genotypes and approximately 40-50% of liver tumors showed activating mutations in codon 61 of the Ha-Ras gene independent of genotype. Moreover, only very few P53-positive lesions were observed but without nuclear localization of the protein, suggesting the absence of P53 mutations. These data suggest that the hupki allele behaves like its murine ortholog in mouse hepatocarcinogenesis.

B-Raf and Ha-ras mutations in chemically induced mouse liver tumors

The mitogen-activated protein kinase signalling pathway is a central regulator of tumor growth, which is constitutively activated in chemically induced mouse liver tumors. In about 30-50% of cases this effect can be related to activation of the Ha-ras gene by point mutations, whereas in the remaining cases mutations may occur in other members within this pathway, such as Raf kinases. Recently, B-raf has been shown to be frequently mutated in human melanomas and certain other cancers, with a V599E amino-acid change representing the most predominant mutation type. We now screened 82 N-nitrosodiethylamine-induced liver tumors from C3H/He mice for mutations within the hotspot positions in the Ha-ras and B-raf genes. About 50% (39/82) of tumors showed Ha-ras codon 61 mutations and 16 tumors ( approximately 20%) harbored mutations at codon 624 of the B-raf gene, which corresponds to codon 599 in human B-raf. None of the tumors was mutated in both Ha-ras and B-raf. The high prevalence of Ha-ras and B-raf mutations in mouse liver tumors is in striking contrast to human hepatocellular cancers which very infrequently harbor mutations in the two genes. These fundamental differences between the biology of liver tumors in mice and man may be of toxicological relevance.

GLOB-1: a prospective randomised clinical phase III trial comparing vinorelbine-cisplatin with vinorelbine-ifosfamide-cisplatin in metastatic non-small-cell lung cancer patients

BACKGROUND

The standard doublet, vinorelbine-cisplatin, was compared with a triplet of vinorelbine-ifosfamide-cisplatin, in terms of survival, in patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

From February 1998 to June 1999, 259 chemonaïve patients entered the study and were randomised to receive either vinorelbine-cisplatin (NP; vinorelbine 30 mg/m(2) on days 1, 8 and 15 with cisplatin 80 mg/m(2) on day 1) or vinorelbine-ifosfamide-cisplatin (NIP; vinorelbine 25 mg/m(2) on days 1 and 8, ifosfamide 3 g/m(2) on day 1 and cisplatin 75 mg/m(2) on day 1), with both regimens being repeated every 3 weeks. All patients had stage IV or relapsed disease and a performance score of 0 or 1.

RESULTS

The overall response rate was 34.6% for NP and 35.7% for NIP. Median and 1-year survival rates were 10.0 months and 38.4% for NP, and 8.2 months and 33.7% for NIP, respectively. A median of four cycles was administered in each arm. The major World Health Organization grade 3-4 toxicities for NP and NIP, respectively, were: neutropenia (20.3% compared with 9% of cycles), anaemia (4.1% compared with 5% of cycles), nausea and vomiting (22.2% compared with 19.4% of patients) and alopecia (5.6% compared with 29.8% of patients). Four toxic deaths occurred in the NP arm and eight in the NIP arm.

CONCLUSIONS

The different schedules of vinorelbine in the two arms led to a greater survival in the NP arm without impairing the tolerance profile, although this is not statistically significant. This confirms that the two-drug combination NP is a reference treatment for metastatic NSCLC. The role of three-drug combinations remains questionable in this subset of patients.

[Progress in measurement of the calcaneus using ultrasonic methods in children and adolescents]

At present, Dual Energy X-ray Absorptiometry (DEXA) method is a reference method to diagnose osteoporosis. This method allows to measure bone density and bone mass, however bone quality can not be estimated. Quantitative ultrasound (QUS) method provides information about bone structure. The aim of our work was the evaluation of QUS method in healthy children, establishing reference values in cross-sectional study of healthy children aged 7-18 yrs and to examine the annual change of ultrasound parameters in prospective study at pubertal. Group of 530 girls and 369 boys was recruited from Warsaw schools, and right heel was measured with Achilles Plus apparatus. Measurements were repeated after 1 year, in a subgroup of 153 children aged 9-13 yrs. The method was adapted for paediatric measurements by using limiter of ultrasonic wave and pads for positioning foot in water chamber. Speed of sound (SOS) and broadband ultrasound attenuation (BUA) were measured and Stiffness index was calculated. Width of heel, at the same location as QUS measurement, was also measured using calipers. SOS, BUA and Stiffness values increased by age in boys and girls. BUA and Stiffness values were significantly higher in 15, 16 and 17 year old boys than in age-matched girls (in 18 yrs--only Stiffness). However, there were no significant sex differences in annual increase of SOS, BUA and Stiffness, although the biggest increase was observed between the age of 13-14 yrs for boys and 11-12 yrs for girls. That may reflect pubertal spurt of body growth but that relationship was not confirmed by annual increases calculated from cross-sectional data. Statistically significant correlation of SOS, BUA and Stiffness with body mass, height, body mass index (BMI) and heel width was observed. Normalization of SOS, BUA and Stiffness on heel width decreased force of that correlation but it was still statistically significant. Dynamics of SOS, BUA and Stiffness increase by age was higher in boys than in girls. This phenomenon is probably related to higher peak bone mass in men than in women, and lower risk of fracture in men, especially concerning hip. Increase of speed of sound, broadband ultrasound attenuation and stiffness index by age, and their correlations with body mass, height and body mass index reflects bone growth in children and adolescents. Broadband ultrasound attenuation and Stiffness index show sex differences in bone development in adolescence. Higher dynamics of the increase of speed of sound, broadband ultrasound attenuation and Stiffness index by age in boys confirms faster bone mass accumulation in boys than in girls.

Dielectric resonator-based side-access probe for muscle fiber EPR study

We present a novel dielectric resonator (DR)-based resonant structure that accommodates aqueous sample capillaries in orientations that are either parallel (i.e., side-access) or perpendicular to the direction of an external (Zeeman) magnetic field, B(0). The resonant structure consists of two commercially available X-band DRs that are separated by a Rexolite spacer and resonate in the fundamental TE(01delta) mode. The separator between the DRs is used to tune the resonator to the desired frequency and, by appropriately drilled sample holes, to provide access for longitudinal samples, notably capillaries containing oriented, spin-labeled muscle fibers. In contrast to the topologically similar cylindrical TE(011) cavity, the DR-based structure has distinct microwave properties that favor its use for parallel orientation of lossy aqueous samples. For perpendicular orientation of a dilute (6.25 microM) aqueous solution of IASL spin label, the S/N ratio was at least one order of magnitude better for the side-access DR-based structure than for a standard TE(102) cavity. EPR spectra acquired for maleimide spin-labeled myosin filaments also revealed ca. 10 times better S/N ratio than those obtained with a standard TE(102) cavity. For the side-access DR with sample capillaries oriented either parallel or perpendicular to the external magnetic field, the Q- and filling factors are in good agreement with the theoretical estimates derived from the distribution of magnetic (H(1)) and electric (E(1)) components.

[Intrahepatic portocaval shunt as a new method for treating and prevention of bleeding from esophageal varices in portal hypertension]

The aim of this study was the presentation of percutaneous transjugular intrahepatic porto-systemic shunt (TIPS) and its place among the other methods of the treatment of esophageal variceal bleedings. In the period from June 1992 to December 1997, 31 cirrhotic patients with portal hypertension and recurrent variceal bleedings were submitted for TIPS. This group consisted of 14 female and 17 male patients, their age ranging from 17 to 68 years (average 52). According to Child-Pugh classification 4 patients represented group A, 11--group B and 16--group C. Each of these patient was admitted to our Department after recurrent bleeding, resistant to typical treatment: terlipressein infusion, balloon tamponade and endoscopic sclerotherapy. In 24 patients (78%) TIPS was performed successfully. In 7 cases TIPS was performed in candidates for orthotopic liver transplantation.

CONCLUSIONS

TIPS is quite new, nearly 10 years old method for portal decompression. It is an effective and less invasive method than surgical procedures in the treatment of portal hypertension, especially in Child-Pugh group B and C patients if the sclerotherapy is not effective. It protects cirrhotic patients waiting for liver transplantation against the esophageal bleedings.

Erratic evolution of glycerol-3-phosphate dehydrogenase in Drosophila, Chymomyza, and Ceratitis

We have studied the evolution of Gpdh in 18 fruitfly species by sequencing 1,077 nucleotides per species on average. The region sequenced includes four exons coding for 277 amino acids and three variable-length introns. Phylogenies derived by a variety of methods confirm that the nominal genus Zaprionus belongs within the genus Drosophila, whereas Scaptodrosophila and Chymomyza are outside. The rate of GPDH evolution is erratic. The rate of amino acid replacements in a lineage appears to be 1.0 x 10(-10)/site/year when Drosophila species are considered (diverged up to 55 million years ago), but becomes 2.3 x 10(-10) when they are compared to Chymomyza species (divergence around 60 My ago), and 4.6 x 10(-10) when species of those two genera are compared with the medfly Ceratitis capitata (divergence around 100 My ago). In order to account for these observations, the rate of amino acid replacement must have been 15 or more times greater in some lineages and at some times than in others. At the nucleotide level, however, Gpdh evolves in a fairly clockwise fashion.

Double-stacked dielectric resonator for sensitive EPR measurements

A new approximate method for predicting the resonant frequencies and for solving the field distribution problem of a cylindrical dielectric resonator (DR) is developed. The model proposed in this paper bridges the gap between rigorous and accurate finite-element or Green function-based numerical methods on the one hand and on the other hand, simple approximate solutions in which the field distribution can be described analytically, but the resulting frequency is accurate within a few percent only. In the method described here, the approximate solution for the microwave field distribution is modified by substituting different values of the radial separation constants inside and outside of the diskshaped DR. The model is generalized for the double-stacked DR structure and enables one to introduce corrections that take into account the presence of the shielding walls and of the cylindrical sample hole. Good agreement is found between experimental and calculated results for both the single and double-stacked structures that are designed around commercially available X-band DRs (9-10 GHz). For the resonant frequency of the lowest transverse-electric TEzero1 delta mode that is commonly used for EPR measurements, the accuracy of the method is better than 1%. Experimentally measured resonator filling factors are also in good agreement with those theoretically estimated. Both the theory and the experimental results suggest that the double-stacked DR structure with finite spacing between the ceramic cylinders is the most suitable for EPR measurements of long lossy samples.

A minimal medium for growth of Pasteurella multocida

We developed a minimal medium supporting the growth of both toxigenic and nontoxigenic strains of Pasteurella multocida to optical densities of > 0.5 (600 nm). P. multocida P1059 (ATCC 15742), one of a number of strains which can cause fowl cholera, was used as the model strain in this study. The medium was composed of 17 ingredients including cysteine, glutamic acid, leucine, methionine, inorganic salts, nicotinamide, pantothenate, thiamine, and an energy source. Leucine was not required for growth but was stimulatory, and thiamine could be replaced by adenine. An additional 46 strains of P. multocida were tested, and 40 out of 46 (87%) strains grew as well as strain P1059 through a minimum of 10 serial transfers. P. multocida toxin (PMT) was produced when cells of a known toxigenic strain (P4261) were cultivated in the minimal medium. No growth of Pasteurella Haemolytica or Pasteurella trehalosi strains was observed in this minimal medium.

[Measurements of calcaneus bone density by ultrasonography in children and adolescents]

In recent years the interest in growing in the use of ultrasonographic method for the assessment of bony tissue density. However, studies using this method were conducted almost exclusively in adult patients. The aim of this study was to apply this method for measurements in children in wide age range (7-18 years) and to determine value range of the parameters SOS, BUA and Stiffness for children in Warsaw in age and sex groups. The studies included 233 children of either sex, aged 7-18 years, healthy on medical examination coming from Warsaw schools. Achilles (Lunar Corp. WI, USA) bone densitometer was used with producer's software, 1.5c version. During examination with the Achilles device, the velocities of ultrasound beam passage through the calcaneus (SOS m/s) and the damping factor of ultrasound wave depending on its frequency (BUA db/MHz) were measured. Additionally the so called "stiffness factor" was calculated. The Achilles device was adapted for measurements in children reducing the diameter of the measuring beam to 1 cm and using pads positioning the child's foot in the device. Equal increase of SOS, BUA and Stiffness parameters with age was observed with the exception of the SOS parameter in girls which increased intensively from 7 to 12 years of age while over 12 years of age its increase was slight. Using linear regression analysis it was found that the values of SOS, BUA and Stiffness parameters depended directly proportionally on age, body weight and height. Respective correlation factors (r) were from 0.49 (body weight-SOS to 0.80 (height-BUA). The observed dependence of the SOS, BUA and Stiffness parameters on body weight, height and especially age enables presuming that the results of calcaneus density measurements by ultrasonographic method reflect the skeletal development in children.

Ultrasound bone measurement in pediatric subjects

Ultrasound bone measurement in healthy (n = 71) and osteopenic (n = 18) children aged 6 through 13 years of both sexes has been evaluated using the Achilles densitometer (Lunar Corporation). Measurements on the os calcis included speed of sound (SOS), broadband ultrasound attenuation (BUA), and a calculated "stiffness" index. The Achilles was adapted for children by a special positioning procedure that included the use of foot shims, and beam collimation on the receiving transducer. The precision of ultrasound results was comparable to that in adults (0.2% for SOS, 1.5% for BUA, and 1.8% for stiffness). SOS, BUA, and stiffness values increased with age in both sexes. Ultrasound measurements were correlated with bone mineral density (BMD in g/cm2) of the heel, AP spine (L2-L4), and total body by dual X-ray absorptiometry (DXA) densitometry (Lunar DPX-L). SOS, BUA, and stiffness measurements were significantly lower in osteopenic children (Z approximately -1.9 to -2.5) (P < 0.0001) than in normal age-matched controls. Total body BMD showed a higher Z-score than stiffness (-3.3 versus -2.5), but stiffness showed a greater percentage decrease (-30% versus -18%). In conclusion, ultrasound measurements of bone in children provide both good precision and discrimination of normals from osteopenic patients.

[A case of multiple intracranial meningiomas]

A case of a 58-year old woman in whom two meningiomas were discovered and removed successfully is presented. One of the meningiomas belonged to tentorial meningioma and was localized in the posterior fossa, compressing the right cerebellar hemisphere and fourth ventricle and finally producing obstructive hydrocephalus. The second was parasagittal meningioma and was localized in the frontal region on the left side. The patient was operated in two stages--first ventricular drainage was applied and posterior fossa meningioma was successfully removed totally with coagulation of the dural attachment. In the second stage, one month after the first operation parasagittal meningioma was removed totally, dural attachment was thoroughly coagulated. The patient had a good outcome is self dependent and able to carry on normal activity.

[Measurements of bone mineral density of the calcaneus in children with ultrasonic methods]

The study aimed at determining precision and accuracy of the ultrasound technique measuring bone mineral density in the calcaneus bone in children. Bone densitometer of Achilles type was adapted for measurements in children. Ultrasound beam was narrowed and a system of special pads positioning the foot were used for this purpose. Precision (CV (%) SOS: phantom 0.42, patients -0.42; BUA: phantom 1.46, patients -3.03) and accuracy of this technique were determined in comparison with dual energy X-ray absorptiometry as well as its value in diagnosis of osteopenia in childhood. An increase in SOS and BUA with the age was found. A decrease in these parameters was noted in children with osteopenia, comparing with the values in healthy children. Significant correlations (r ranging from 0.50 to 0.91) between ultrasound and DEXA techniques were seen. The results suggest that ultrasound technique might be useful in pediatric densitometry.

Integrated genetic databases in the study of neuropsychiatric diseases: inborn errors of cerebral metabolic pathways?

1. Genetic databases are an expanding and readily accessible repository of information on the mapping and sequencing of the human genome, and that of other model organisms. The integration and application of this information to neuropsychiatric disease is illustrated using neuroendocrine and neuropharmacologic data, computerized and other genetic databases. 2. This computer-assisted integrated approach to knowledge structures permits the rapid generation of hypotheses, the prompt identification of candidate gene loci, an explanation for genetic heterogeneity, and strategies for the use of potential linked markers. 3. Results using this integrated search strategy demonstrate that over 30 candidate loci for neuropsychiatric disease have currently been mapped in man (spread over 14 chromosomes in the human genome), and that at least 6 homologous loci have been mapped in mouse. 4. Using a metabolic pathway approach, it can be shown that the best current candidate gene locus for a subtype of schizophrenia located on chromosome 5q11-13 (HGML10 # SCZD1 and OMIM #181510) is in the serotonergic pathway, i.e. a receptor for 5-hydroxytryptamine (subtype 1A; HGML10 #HTR1A) which also maps in the same chromosomal region. 5. Parallels are suggested between inborn errors of metabolic pathways in the somatic endocrine system (using insulin-dependent diabetes mellitus as a paradigm) and the neurotransmitter and hormonal systems within the brain. 6. A subset of neuropsychiatric disorders may thus be viewed as inborn errors of cerebral metabolic pathways primarily affecting the biogenic amine pathways.

Computed tomography of the head in the evaluation of microcephaly

Eighty-five infants and children found to have microcephaly had computed tomographic (CT) brain scans performed. A greater degree of microcephaly correlated with the finding of atrophy or ventricular dilation on CT scan. Patients who had known preceding destructive brain insults had the highest incidence of abnormal findings on scans (20/22). Patients who had CNS dysfunction of unknown etiology had the lowest frequency of abnormal findings (12/33); however, in three of these patients, a previously unsuspected brain malformation was found on CT scan. Patients who had other congenital anomalies had an intermediate proportion of abnormal findings on CT scans (20/30), and in 11 of these scans, a previously unsuspected or only partly suspected brain malformation was diagnosed. Discovering previously unsuspected information or finding supportive data regarding the basis for the underlying disease process, being able to provide a more specific developmental prognosis and accurate genetic counseling, justifies the inclusion of a CT scan of the head in the evaluation of the microcephalic child.

Townes syndrome. A distinct multiple malformation syndrome resembling VACTERL association

An 8-year-old male is presented with clinical findings of Townes syndrome in an otherwise unaffected family. Additional abnormalities possibly representing low frequency associations of this autosomal dominant multiple malformation syndrome included a cardiac defect and hypospadias. Similarities exist between Townes syndrome and VACTERL association, which is generally regarded to be sporadic in nature. Recognition of Townes syndrome as a distinct entity is critical for implementing appropriate management in early childhood, including amplification of hearing impairments. Variable expressivity may occur in this disorder. Careful evaluation must be made, therefore, of the parents of an affected infant with an apparent sporadic case, in order to provide the couple with an accurate recurrence risk at genetic counseling.

High-pressure EPR cavity

A high-pressure resonant cavity for sensitive EPR measurements is described. The cavity operating in the TE(115) cylindrical mode enables EPR experiments to be carried out in the 77-300 K temperature range at high hydrostatic pressure up to 8 kilobar.