2'-deoxy-ADPR activates human TRPM2 faster than ADPR and thereby induces higher currents at physiological Ca2+ concentrations

TRPM2 is a Ca2+ permeable, non-selective cation channel in the plasma membrane that is involved in the innate immune response regulating, for example, chemotaxis in neutrophils and cytokine secretion in monocytes and macrophages. The intracellular adenine nucleotides ADP-ribose (ADPR) and 2'-deoxy-ADPR (2dADPR) activate the channel, in combination with their co-agonist Ca2+. Interestingly, activation of human TRPM2 (hsTRPM2) by 2dADPR is much more effective than activation by ADPR. However, the underlying mechanism of the nucleotides' differential effect on the channel is not yet fully understood. In this study, we performed whole-cell patch clamp experiments with HEK293 cells heterologously expressing hsTRPM2. We show that 2dADPR has an approx. 4-fold higher Ca2+ sensitivity than ADPR (EC50 = 190 and 690 nM). This allows 2dADPR to activate the channel at lower and thus physiological intracellular Ca2+ concentrations. Kinetic analysis of our data reveals that activation by 2dADPR is faster than activation by ADPR. Mutation in a calmodulin binding N-terminal IQ-like motif in hsTRPM2 completely abrogated channel activation by both agonists. However, mutation of a single amino acid residue (W1355A) in the C-terminus of hsTRPM2, at a site of extensive inter-domain interaction, resulted in slower activation by 2dADPR and neutralized the difference in rate of activation between the two agonists. Taken together, we propose a mechanism by which 2dADPR induces higher hsTRPM2 currents than ADPR by means of faster channel activation. The finding that 2dADPR has a higher Ca2+ sensitivity than ADPR may indicate that 2dADPR rather than ADPR activates hsTRPM2 in physiological contexts such as the innate immune response.

Abstract 3724: RAI2 controls polycomb-mediated repression of CDKN1A by its interaction with CtBP1

RAI2 has initially been identified as a metastasis-associated gene in breast cancer. Recently, we found that increased RAI2 protein in primary tumors predicts early biochemical relapse of prostate cancer patients. On the molecular level, RAI2 interacts with CtBP1 as transcriptional co-repressors via a non-consensus tandem ALDLS-motif in hormone-dependent cancer cells. In this study, we aim to investigate the cell-biological relevance of this molecular interaction in prostate cancer cells using the CDKN1A gene as an example of a transcriptional target of CtBP-mediated gene regulation.

To analyze a molecular relation between the RAI2/CtBP1 interaction and repressor of the CDKN1A gene, we first applied a transactivation assay in 293T cells, transiently transfected with CtBP1 and different RAI2 protein variants. Next, we depleted the RAI2 protein in VCaP prostate cancer cells. We used this cell line model to analyze gene expression and protein concertation of RAI2, CtBPs and p21 under different conditions. We studied the subcellular localization and chromatin binding of the proteins of interest by confocal laser-scanning microscopy and ChIP analysis.

The gene reporter assay revealed that combined overexpression of RAI2 and CtBP1 reliefs the repression of the proximal CDKN1A-promotor and that RAI2 with an intact ALDLS tandem motif is required for this process. RAI2 depletion in VCaP cells resulted in a significant reduction of both CtBP1 and CtBP2 and almost complete abolishment of p21 protein levels, which is accompanied by reduced interaction of RAI2 with CtBP1 in nuclei. In parental VCaP cells, genotoxic stress significantly induced CDKNA1 gene expression and p21 protein concentration. In contrast, in RAI2-depleted VCaP cells we did not observe any of these effects, demonstrating the requirement of RAI2 to cause the relief of CDKNA1 repression. RAI2 together with CtBP1 appeared as definite foci in the nuclei of VCaP cells that are co-localized with key factors of polycomb 1 and 2. The ChIP analysis revealed that RAI2-depletion significantly induced binding of CtBPs to the CDKN1A promoter. In contrast, the binding of the polycomb protein LCoR to chromatin is significantly reduced in RAI2-depleted cells. Irrespective of the RAI2 status, the EZH2 binding to the chromatin remained unaltered, whereas a significant increase in H3K27me3 in RAI2-depleted cells was observed.

In summary, we found that interruption of the interaction of RAI2 with CtBP1 is leading to increased chromatin binding of CtBP1 and trimethylation of H3K27 of the CDKN1A promotor, which is associated with repression of CDKN1A gene expression. We conclude that the molecular interaction of RAI2 with CtBP1 is a new molecular mechanism of corepression by modulating the histone-modifications of the target gene.

Citation Format: Sarah Greimeier, Bettina Steinbach, Simon Sander, Lina Merkens, Nishit Goradia, Matthias Wilmanns, Eric Metzger, Klaus Pantel, Stefan Werner. RAI2 controls polycomb-mediated repression of CDKN1A by its interaction with CtBP1. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3724.

New insights into P2X7 receptor regulation: Ca2+-calmodulin and GDP bind to the soluble P2X7 ballast domain

P2X7 receptors are nonselective cation channels that are activated by extracellular ATP and play important roles in inflammation. They differ from other P2X family members by a large intracellular C-terminus that mediates diverse signaling processes that are little understood. A recent cryo-EM study revealed that the C-terminus of the P2X7 receptor forms a unique cytoplasmic ballast domain that possesses a GDP-binding site as well as a dinuclear Zn²⁺ site. However, the molecular basis for the regulatory function of the ballast domain as well as the interplay between the various ligands remain unclear. Here, we successfully expressed a soluble trimeric P2X7 ballast domain (P2X7BD) and characterized its ligand binding properties using a biophysical approach. We identified calmodulin (CaM)-binding regions within the ballast domain and found that binding of Ca²⁺-CaM and GDP to P2X7BD have opposite effects on its stability. Small-angle X-ray scattering experiments indicate that Ca²⁺-CaM binding disrupts the trimeric state of P2X7BD. Our results provide a possible framework for the intracellular regulation of the P2X7 receptor.

Cryo-EM structure of MsbA in saposin-lipid nanoparticles (Salipro) provides insights into nucleotide coordination

The ATP-binding cassette transporter MsbA is a lipid flippase, translocating lipid A, glycolipids, and lipopolysaccharides from the inner to the outer leaflet of the inner membrane of Gram-negative bacteria. It has been used as a model system for time-resolved structural studies as several MsbA structures in different states and reconstitution systems (detergent/nanodiscs/peptidiscs) are available. However, due to the limited resolution of the available structures, detailed structural information on the bound nucleotides has remained elusive. Here, we have reconstituted MsbA in saposin A-lipoprotein nanoparticles (Salipro) and determined the structure of ADP-vanadate-bound MsbA by single-particle cryo-electron microscopy to 3.5 Å resolution. This procedure has resulted in significantly improved resolution and enabled us to model all side chains and visualise detailed ADP-vanadate interactions in the nucleotide-binding domains. The approach may be applicable to other dynamic membrane proteins.

cADPR Does Not Activate TRPM2

cADPR is a second messenger that releases Ca²⁺ from intracellular stores via the ryanodine receptor. Over more than 15 years, it has been controversially discussed whether cADPR also contributes to the activation of the nucleotide-gated cation channel TRPM2. While some groups have observed activation of TRPM2 by cADPR alone or in synergy with ADPR, sometimes only at 37 °C, others have argued that this is due to the contamination of cADPR by ADPR. The identification of a novel nucleotide-binding site in the N-terminus of TRPM2 that binds ADPR in a horseshoe-like conformation resembling cADPR as well as the cADPR antagonist 8-Br-cADPR, and another report that demonstrates activation of TRPM2 by binding of cADPR to the NUDT9H domain raised the question again and led us to revisit the topic. Here we show that (i) the N-terminal MHR1/2 domain and the C-terminal NUDT9H domain are required for activation of human TRPM2 by ADPR and 2'-deoxy-ADPR (2dADPR), (ii) that pure cADPR does not activate TRPM2 under a variety of conditions that have previously been shown to result in channel activation, (iii) the cADPR antagonist 8-Br-cADPR also inhibits activation of TRPM2 by ADPR, and (iv) cADPR does not bind to the MHR1/2 domain of TRPM2 while ADPR does.

Microstructured layered targets for improved laser-induced x-ray backlighters

We present the usage of two-layer targets with laser-illuminated front-side microstructures for x-ray backlighter applications. The targets consisted of a silicon front layer and copper back side layer. The structured layer was irradiated by the 500-fs PHELIX laser with an intensity above 10^{20}Wcm^{-2}. The total emission and one-dimensional extent of the copper Kα x-ray emission as well as a wide spectral range between 7.9 and 9.0 keV were recorded with an array of crystal spectrometers. The measurements show that the front-side modifications of the silicon in the form of conical microstructures maintain the same peak brightness of the Kα emission as flat copper foils while suppressing the thermal emission background significantly. The observed Kα source sizes can be influenced by tilting the conical microstructures with respect to the laser axis. Overall, the recorded copper Kα photon yields were in the range of 10^{11}sr^{-1}, demonstrating the suitability of these targets for probing applications without subjecting the probed material to additional heating from thermal line emission.

Surgery due to mechanical bowel obstruction in relapsed ovarian cancer: clinical and surgical results of a bicentric analysis of 87 patients

Introduction

Mechanical bowel obstruction is a frequent acute and life-threatening event in relapsed ovarian cancer. Salvage surgery after failure of all conservative approaches, resulting in short bowel syndrome (SBS) constitutes a therapeutic dilemma. Our aim was to evaluate patients’ surgical and clinical outcome in these highly palliative situations. Previous, limited, data reported a high morbidity and mortality. However, recent surgical and therapeutical improvements in relapsed ovarian cancer (ROC) offer better identification of patients who might benefit from surgery in an effort to extend the window of opportunity to subsequently offer these patients novel systemic therapeutic approaches.

Material and methods

All subsequent ROC patients between 2012 and 2017 with acute mechanical bowel obstruction who underwent salvage extraperitoneal en bloc intestinal resection were retrospectively identified. Data were collected from two ESGO certified Ovarian Cancer Centers of Excellence (Charité Berlin and Imperial College London) and systematically evaluated regarding surgical and clinical outcomes.

Results

Overall, 87 ROC patients were included in the analysis (median age 56 years, range 24–88), 47% were platinum resistant. High grade serous was the most common histology (76%) while most of the patients (67%) had at least two previous lines of treatment. Mean observed OS was 7.8 months. After salvage surgery, 46% of the patients had a residual small bowel length < 180 cm and 18% > 180 cm resulting in 41% in need of total parental nutrition. In 80% of the patients a permanent stoma was necessary. 30d morbidity and mortality was 74% and 10%, respectively. More than half of the patients were able to receive further courses of chemotherapy after surgery.

Discussion

Salvage surgery for bowel obstruction in ROC patients needs careful consideration and identification of optimal surgical candidates to have the maximal therapeutic benefit. Despite the challenging morbidity profile, most patients managed to proceed to subsequent novel and conventional systemic treatment and so have their window of therapeutic opportunity extended.

Analysis of ligand binding and resulting conformational changes in pyrophosphatase NUDT9

Nudix hydrolase 9 (NUDT9) is a member of the nucleoside linked to another moiety X (NUDIX) protein superfamily, which hydrolyses a broad spectrum of organic pyrophosphates from metabolic processes. ADP‐ribose (ADPR) has been the only known endogenous substrate accepted by NUDT9 so far. The Ca²⁺‐permeable transient receptor potential melastatin subfamily 2 (TRPM2) channel contains a homologous NUDT9‐homology (NUDT9H) domain and is activated by ADPR. Sustained Ca²⁺ influx via ADPR‐activated TRPM2 triggers apoptotic mechanisms. Thus, a precise regulation of cellular ADPR levels by NUDT9 is essential. A detailed characterization of the enzyme‐substrate interaction would help to understand the high substrate specificity of NUDT9. Here, we analysed ligand binding to NUDT9 using a variety of biophysical techniques. We identified 2′‐deoxy‐ADPR as an additional substrate for NUDT9. Similar enzyme kinetics and binding affinities were determined for the two ligands. The high‐affinity binding was preserved in NUDT9 containing the mutated NUDIX box derived from the human NUDT9H domain. NMR spectroscopy indicated that ADPR and 2′‐deoxy‐ADPR bind to the same binding site of NUDT9. Backbone resonance assignment and subsequent molecular docking allowed further characterization of the binding pocket. Substantial conformational changes of NUDT9 upon ligand binding were observed which might allow for the development of NUDT9‐based ADPR fluorescence resonance energy transfer sensors that may help with the analysis of ADPR signalling processes in cells in the future.

Improving aeration systems in saline water: measurement of local bubble size and volumetric mass transfer coefficient of conventional membrane diffusers

In this study, for the first time, the influence of the design of conventional membrane diffusers on the volumetric mass transfer coefficient (k_La) and bubble size in tap water (TW) and saline water (SW) was investigated (up to 15 g/L NaCl). By using a new analytical approach, k_La and the bubble size along the ascent of the bubble swarm were measured simultaneously and in real time. The results show that in TW, after collision bubbles merge into larger bubbles by coalescence. In SW, coalescence is inhibited by salt. Due to the smaller bubble size, k_La increases to more than double compared to TW. The results show that in SW, membrane diffusers with dense slit patterns and smaller slit lengths are to be recommended in order to enable improved utilization of oxygen in saline water.

Abstract P1-01-07: Clinical and histological characteristics of peritoneal metastases of invasive lobular breast cancer

Introduction: In previously reported autopsy series, peritoneal metastases have been detected in up to 40% of patients with invasive lobular breast cancer (ILC). Despite modern diagnostic techniques such as high-resolution ultrasound, it remains a challenge to differentiate ovarian cancer from metastatic breast cancer with peritoneal manifestation before or during surgery. The goal of this analysis was to determine typical clinical and immunohistological features of peritoneal metastasis of ILC. Specifically, we asked the question whether there are predictive factors in primary breast cancer associated with subsequent development of peritoneal metastasis. Patients and methods: We identified 58 patients with ovarian metastases in the Charité cancer register (4,792 breast cancer patients from 2003 to 2015). We looked for clinical and pathological differences between breast cancer patients with (N=58) and without (N=4734) peritoneal metastases and between ILC and non-ILC breast cancer subtypes. Imaging and surgical reports of these 58 patients with ILC intraperitoneal metastases were reviewed. Results: The majority (84.7%) of primary breast cancers consisted of subtypes other than ILC and only 15.3% were histologically characterized as ILC. In contrast, 63.6% of patients with peritoneal metastases had histologically proven ILC in the metastatic tissue. Other subtypes where found in the 36.4% of the metastatic tissue (p&lt;0.001). The Odds ratio for peritoneal metastases for ILC was 2.35 (95% CI 1.655-3.332) and for Non-ILC 0.23 (0.185-0.284). There were no significant differences in receptor status between primary and peritoneal metastatic ILC. Comparing ER/PR expressions levels on primary tumor versus metastasis, while statistically not significant (p= 0.805), showed a rise in ER expression in 42.95% in the metastatic tissue while PR expression remained stable with no difference in 53.3% and a rise in the metastatic site in only 26.7% (p= 0.715). Median age of all patients with primary breast cancer was 60 years (10%-90%: 41-75). There was a significant difference in age at diagnosis of metastasis between patients with (50.5 years) and without peritoneal metastases (59 years) (p= 0.002). Median time to development of peritoneal metastases for all patients was 48.5 months (10%-90%: 0-191.7), for ILC 44 months (0-198.2) and for Non-ILC 56.5 months (6.7-206.4) (p= 0.487). Median survival time for patients with ILC and peritoneal metastases was 56 months, for Non-ILC 53 months (p=0.759). 33 of 58 patients had radiologic evidence of disease, 26 with ILC and 7 with Non-ILC. An ovarian mass was detected by imaging in 15/26 patients with ILC and 4/7 patients with non-ILC. Ascites and diffuse peritoneal metastases were seen in 18/26 patients with detectable ILC and in 4/7 patients with Non-ILC.

Conclusion: This is the first comprehensive analysis of clinical and pathological characteristics of peritoneal metastases showing ILC is more frequent than other histologic subtypes. Patients with peritoneal metastasis are significantly younger (median 50.5y.) than patients without. The clinical signs are similar to those of ovarian cancer except and therefore the diagnosis of metastatic ILC must be taken into consideration as a differential diagnosis.

Citation Format: Karsten MM, Ingold-Heppner B, Oesterreich S, Sander S, Machleidt A, von Waldenfels G, Denkert C, Blohmer JU. Clinical and histological characteristics of peritoneal metastases of invasive lobular breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-01-07.

Design of fine-bubble aeration systems for municipal WWTPs with high sea salt concentrations

The impact of sea salt on the aeration coefficient k_La of fine-bubble aeration systems was investigated in clean water and in a model substance for simulating activated sludge. The investigations were carried out at laboratory and pilot scale. Sea salt was dosed in the form of artificial seawater, real seawater or simplified, by adding NaCl. The investigated media showed an increase of k_La with rising sea salt concentrations up to 10 g/L. The ratio between k_La and sea salt concentration is impaired by the air flow rate and the type of applied diffusers. Literature data show that the favourable effect of sea salt on k_La can also be found in the activated sludge of conventional municipal wastewater treatment plants. The results of this study allow the derivation of salt correction equations to be used in the design of fine-bubble aeration systems for taking into account the favourable impact of sea salt on k_La. By that means, a more precise design of respective systems will be enabled.

Energy, cost and design aspects of coarse- and fine-bubble aeration systems in the MBBR IFAS process

With the MBBR IFAS (moving bed biofilm reactor integrated fixed-film activated sludge) process, the biomass required for biological wastewater treatment is either suspended or fixed on free-moving plastic carriers in the reactor. Coarse- or fine-bubble aeration systems are used in the MBBR IFAS process. In this study, the oxygen transfer efficiency (OTE) of a coarse-bubble aeration system was improved significantly by the addition of the investigated carriers, even in-process (∼1% per vol-% of added carrier material). In a fine-bubble aeration system, the carriers had little or no effect on OTE. The effect of carriers on OTE strongly depends on the properties of the aeration system, the volumetric filling rate of the carriers, the properties of the carrier media, and the reactor geometry. This study shows that the effect of carriers on OTE is less pronounced in-process compared to clean water conditions. When designing new carriers in order to improve their effect on OTE further, suppliers should take this into account. Although the energy efficiency and cost effectiveness of coarse-bubble aeration systems can be improved significantly by the addition of carriers, fine-bubble aeration systems remain the more efficient and cost-effective alternative for aeration when applying the investigated MBBR IFAS process.

Factors influencing the course of acute appendicitis in adults and children

PURPOSE

Our aim was to determine predictive factors for the diagnosis and postoperative complications of acute appendicitis.

MATERIALS AND PATIENTS

Data sets of 1,439 consecutive adults and children who had an appendectomy between 1999 and 2008 were retrospectively analyzed.

RESULTS

A mild acute appendicitis was present in 50 % (n = 722) and a severe acute appendicitis in 25 % (n = 355) of the patients. No signs of any pathology were found in 6 % (n = 82). Gender, white blood count (WBC), C-reactive protein (CRP), and ultrasound (US) examination were important indicators of mild acute and severe acute appendicitis in adults and children. Postoperative complications occurred in 16 % (237/1,439), mainly consisting of wound infections (8 %, n = 122) and bowel dysfunction (5 %, n = 76). Sixty-two patients (4.3 %) required reoperations. One patient died (1/1,439, 0.07 % mortality rate). Age, pathology, and the presence of bacteria in the intraoperative swab were important predictive factors for postoperative complications in adults and children. Time since onset of symptoms and type of operation were also associated with postoperative complications among adults. Complications developed in 21 and 9 % of the adults (155/754 and 10/125) who had open and laparoscopic surgery, respectively.

CONCLUSIONS

Besides history and clinical examination, WBC, CRP, and US examination remain important factors for diagnosing acute appendicitis. Complications are related to the pathology, presence of bacteria, and type of operation. Early diagnosis within 48 h may be important. A laparoscopic procedure in adults may also cause fewer wound infections.

[Neurodevelopmental outcome of very low birth weight infants born at the Perinatal Centre in Ulm, Germany]

BACKGROUND

Since 2006 an assessment of the neurodevelopmental outcome of very low birth weight infants (VLBWI) at a corrected age of 2 years is mandatory for every perinatal centre in Germany. The aim of our study was to check how complete these assessments were performed in our population of infants born at our perinatal centre and receiving treatment within our local neonatal network. Furthermore, the data obtained will be used for prenatal consultations. Another objective was to identify risk factors for adverse neurodevelopmental outcomes.

METHODS

All VLBWI were invited for a follow-up exam using the Bayley Scales of Infant Development II (BSID-II) or III (BSID-III), or Griffiths Mental Developmental Scales) at 2 years corrected age. The results of children assessed by other institutions were collected.

RESULTS

142 (69.3%) of the 205 VLBWI, born and finally discharged alive at the perinatal centre in Ulm were assessed at a median (minimum - maximum) corrected age of 23 (18-27) months. The BSID-II Psychomotor Development Index (PDI) 91 was (< 50-128) (n=115), the BSID-II Mental Development Index (MDI) was 87 (< 50-134) (n=96), BSID-III MDI 95 (60-112) (n=29) and the Griffiths Score was 93 (67-140) (n=17). Severe disability was diagnosed in 36 (25.4%) of the children studied. Gestational age and higher grade intraventricular haemorrhage were associated independently with severe disability.

CONCLUSIONS

It is very difficult to achieve a high rate of follow-up examinations in preterm infants <1,500 g in a neonatal network. Severe impairment in VLBWI is not rare. Improving neurodevelopmental outcome remains a challenge.

Rapid quantification of conjugated and unconjugated bile acids and C27 precursors in dried blood spots and small volumes of serum

The aim of the study was to develop a method for fast and reliable diagnosis of peroxisomal diseases and to facilitate differential diagnosis of cholestatic hepatopathy. For the quantification of bile acids and their conjugates as well as C(27) precursors di- and trihydroxycholestanoic acid (DHCA, THCA), in small pediatric blood samples we combined HPLC separation on a reverse-phase C18 column with ESI-MS/MS analysis in the negative ion mode. Analysis was done with good precision (CV 3,7%-11.1%) and sufficient sensitivity (LOQ: 11-91 nmol/L) without derivatization. Complete analysis of 17 free and conjugated bile acids from dried blood spots and 10 microL serum samples, respectively, was performed within 12 min. Measurement of conjugated primary bile acids plus DHCA and THCA as well as ursodeoxycholic acid was done in 4.5 min. In blood spots of healthy newborns, conjugated primary bile acids were found in the range of 0.01 to 2.01 micromol/L. Concentrations of C(27) precursors were below the detection limit in normal controls. DHCA and THCA were specifically elevated in cases of peroxysomal defects and one Zellweger patient.

A meta-analysis of the vascular-related safety profile and efficacy of alpha-adrenergic blockers for symptoms related to benign prostatic hyperplasia

OBJECTIVES

To evaluate the safety profile and efficacy of alpha1-adrenergic receptor blockers (A1Bs) currently prescribed for benign prostatic hyperplasia (BPH).

DATA SOURCES

A systematic literature search of MEDLINE, the Cochrane Database and the Food and Drug Administration Web site through December 2006 identified double-blinded, prospective, placebo-controlled trials, evaluating agents commercially available by prescription for the symptomatic treatment of BPH.

REVIEW METHODS

Data were reviewed by two investigators with the use of a standardised data abstraction form. Studies were evaluated for methodological quality using the Jadad scale. Studies with a score of < 3 were considered of weaker methodology.

RESULTS

Of 2389 potential citations, 25 were usable for evaluation of safety data, 26 for efficacy. A1B use was associated with a statistically significant increase in the odds of developing a vascular-related event [odds ratio (OR) 2.54; 95% confidence interval (CI): 2.00-3.24; p < 0.0001]. The odds of developing a vascular-related adverse event were: alfuzosin, OR 1.66, 95% CI: 1.17-2.36; terazosin, OR 3.71, 95% CI: 2.48-5.53; doxazosin, OR 3.32, 95% CI: 2.10-5.23 and tamsulosin, OR 1.42, 95% CI: 0.99-2.05. A1Bs increased Q(max) by 1.32 ml/min (95% CI: 1.07-1.57) compared with placebo. Difference from placebo in American Urological Association symptom index/International Prostate Symptom Score was -1.92 points (95% CI: -2.71 to -1.14).

CONCLUSIONS

Alfuzosin, terazosin and doxazosin showed a statistically significant increased risk of developing vascular-related events compared with placebo. Tamsulosin showed a numerical increase that was not statistically significant. All agents significantly improved Q(max) and symptom signs compared with placebo.

The most commonly cited articles in pediatric surgical journals

AIM

This study aimed to investigate the characteristics of the most frequently cited articles published in 3 main journals dedicated to the field of pediatric surgery (Journal of Pediatric Surgery, Pediatric Surgery International and European Journal of Pediatric Surgery).

MATERIAL AND METHODS

A search was initiated using the database (1985 - 2006) of the Science Citation Index of the Institute for Scientific Information. The total number of publications and their citation numbers were found and the most cited articles were investigated in detail. A total of 600 (200 from each journal) most cited articles were identified and chosen for further analysis.

RESULTS

The total number of citations in these 3 journals was 20 271. The citations of the most cited articles ranged from 10 to 224. The articles were published between 1985 and 2003 and the mean number of citations/article was 33.78. Articles originated from 39 counties and 256 institutions. The leading countries were the United States (203 articles from 75 institutions), Germany (50 articles from 21 institutions), Japan (34 articles from 17 institutions), Switzerland (34 articles from 8 institutions), United Kingdom (32 articles from 19 institutions), and Canada (28 articles from 7 institutions). Of the institutions with the highest number of cited articles, four institutions were from the USA followed by Switzerland with two institutions. The leading topics were the gastrointestinal system (n = 239), respiratory system (n = 94), urology (n = 61) and oncology (n = 56), and diaphragmatic hernia (n = 41) was the most common special topic. There were 42 case reports (7 %) and 75 experimental research articles (12.5 %). Thirty-four authors from 14 countries and 30 institutions had articles in more than one journal. The most cited author was N. S. Adzick from the USA with 224 citations.

CONCLUSION

In this study, we found that the Journal of Pediatric Surgery predominated with the greatest number of cited articles. The most cited articles, authors and institutions originated from the USA and English-speaking countries. The gastrointestinal system, respiratory system, urology and oncology were the leading topics and diaphragmatic hernia was the most common special topic.

Prognostic factors influencing the survival of patients with colon cancer receiving adjuvant 5-FU treatment

AIM

Adjuvant chemotherapy is recommended for stage III colon cancer. The aim of this study was to identify important prognostic factors among patients with colon cancer receiving adjuvant 5-FU-based treatment.

METHODS

Data sets of 855 colon cancer patients treated between 1992 and 1999 within a multicenter adjuvant trial comparing 5-FU modulation with folinic acid or interfereron-alpha were examined. Backward elimination in a proportional hazards model was used to identify prognostically relevant clinical and pathological factors.

RESULTS

Tumor recurrence (p<0.001), duration of adjuvant treatment (p<0.001), tumor substage (p=0.004), age (p=0.005), grading (p=0.016), treatment-related toxicity (p=0.021), and treatment (p=0.031) were identified in descending order of importance as prognostic factors for overall survival.

CONCLUSIONS

Adjuvant 5-FU-based treatment should be performed for at least 6months with a stepwise adjustment of 5-FU doses until toxicity >WHO II. Substages should be reported separately and used for stratification in future trials due to their broad variation in outcome. In the future, this may result in adjuvant treatment of stage III colon cancer adjusted for the risk of substages.

Expression of estrogen and androgen receptors in children with hypospadias: preliminary report

This investigation was conducted to evaluate the presence of estrogen and androgen receptors in penile tissues of patients with hypospadias. The biopsy specimens from prepuce, glans, and urethral plate were sampled during the hypospadias surgery in five patients and were analyzed immunohistochemically. Twelve specimens were investigated for the presence of estrogen or androgen receptors (n: 24); the result was negative in 9 (37%) and positive in 15 (63%). Estrogen receptors were present in 10 specimens (42%) (prepuce: 5, glans: 3, and urethral plate: 2). Androgen receptors were present in 5 specimens (21%) (prepuce: 3, glans: 1, and urethral plate: 1). There was expression of both estrogen and androgen receptors in 5 specimens and only estrogen receptors in the remaining 5. Dominant expression of estrogen receptors in penile tissues of children with hypospadias may be the postnatal finding of disrupted estrogen and androgen receptor interaction during the intrauterine development of external genitalia.

Newborn screening for congenital adrenal hyperplasia: additional steroid profile using liquid chromatography-tandem mass spectrometry

BACKGROUND

Neonatal screening programs for congenital adrenal hyperplasia (21-CAH) using an immunoassay for 17alpha-hydroxyprogesterone (17-OHP) generate a high rate of positive results attributable to physiological reasons and to cross-reactions with steroids other than 17alpha-OHP, especially in preterm neonates and in critically ill newborns.

METHODS

To increase the specificity of the screening process, we applied a liquid chromatography-tandem mass spectrometry method quantifying 17alpha-OHP, 11-deoxycortisol, 21-deoxycortisol, cortisol, and androstenedione. The steroids were eluted in aqueous solution containing d8-17alpha-OHP and d2-cortisol and quantified in multiple reaction mode.

RESULTS

Detection limit was below 1 nmol/liter, and recovery ranged from 64% (androstenedione) to 83% (cortisol). Linearity was proven within a range of 5-100 nmol/liter (cortisol, 12.5-200 nmol/liter), and total run time was 6 min. Retrospective analysis of 6151 blood samples and 50 blood samples from newborns with clinically confirmed 21-CAH, as well as prospective analysis of 1609 samples of a total of 242,500 testing positive in our routine 17-OHP immunoassay, allowed clear distinction of affected and nonaffected newborns. High levels of 21-deoxycortisol were only found in children with 21-hydroxylase deficiency. Calculating the ratio of 17alpha-OHP to 21-deoxycortisol divided by cortisol further increased the sensitivity of the method.

CONCLUSION

Our liquid chromatography-tandem mass spectrometry procedure as a second-tier test can be used to reduce false-positive results of standard 21-CAH screening. The short total run time of 6 min allows for immediate reanalysis of all immunoassay results above the cutoff.

Molecular profiling reveals myeloid leukemia cell lines to be faithful model systems characterized by distinct genomic aberrations

To model and investigate different facets of leukemia pathogenesis, a widely accepted approach is to use immortalized leukemia cell lines. Although these provide powerful tools to our knowledge, few studies have addressed the question whether hematopoietic cell lines represent accurate and reliable model systems. To improve the molecular characterization of these model systems, we analyzed 17 myeloid leukemia cell lines using DNA microarray technology. By array-based comparative genomic hybridization, we identified recurrent genomic DNA gains and losses, as well as high-level amplifications. Parallel analysis of gene expression helped delineate potential candidate genes, and unsupervised analysis of gene expression data revealed cell lines to cluster in part based on underlying cytogenetic abnormalities. Comparison with clinical leukemia specimens showed that key signatures were retained, as myeloid cell lines with characteristic cytogenetic aberrations co-clustered with leukemia samples carrying the respective abnormality. Signatures were also quite robust, as expression data from cell lines correlated highly with published data. Thus, our analyses demonstrate myeloid cell lines to exhibit conserved and stable signatures reflecting the underlying primary cytogenetic aberrations. Our refined molecular characterization of myeloid cell lines supports the utility of cell lines as faithful and powerful model systems and provides additional insights into the molecular mechanisms of leukemogenesis.

Plasma testosterone and estradiol levels in unilateral cryptorchidism

This research was conducted to investigate the relationship between plasma hormone level during activation of hypothalamic-pituitary-testicular axis at the postnatal period and at puberty in unilateral cryptorchidism. Plasma testosterone and estradiol levels of 80 patients with unilateral cryptorchidism at different ages (range: 6 months-12 years) were measured. The mean plasma testosterone level is 40 (15-60) pg/ml at 6 months of age, 55 (30-120) at ages between 9 and 12 years, and 20 (11-22) at ages between 1 and 9 years. The mean plasma estradiol level is 12, 11 and 11 (5-24) pg/ml, respectively, in these groups. The patients with unilateral cryptorchidism do not have similar peaks of plasma estradiol level as plasma testosterone level at the postnatal period and at puberty. Peak of plasma testosterone at puberty occurs if the patients were not operated on.