Radar evidence of subglacial liquid water on Mars.

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

Pacemaker and ICD oversensing induced by movements near the MRI scanner bore.

PURPOSE: The effect of the movement near the MRI scanner bore for people with a pacemaker (PM) or an implantable cardioverter defibrillator (ICD) is experimentally evaluated and discussed. METHODS: The authors performed in vitro measurements on a saline-filled human-shaped phantom (male, 170 cm height), equipped first with an MR-conditional PM (bicameral configuration, DDD programming), then with an MR-conditional ICD (biventricular configuration, detection algorithms enable but shock delivery disable). Both the devices were able to transmit in real-time the detected cardiac activity (electrograms) while moving the phantom around the MRI scanner. The phantom was also equipped with an accelerometer and a magnetic field probe to measure the angular velocity and the magnetic field variation during the experiment. Unipolar versus bipolar sensing mode and maximum sensitivity versus nominal settings were tested. RESULTS: The sensing functions of the PM and ICD systems began to react to motion induced electromagnetic interference starting at an angular velocity as low as 2 rad/s (|dB/dT| = 2 T/s). The motion induced EMI in PM and ICD systems was interpreted as sensed intrinsic heartbeats which resulted in inappropriate pacing inhibition and arrhythmia classification. At the maximum speed of about 6 rad/s (|dB/dT| = 3 T/s), the induced EMI affected classification of ectopic beats and two episodes of VF were inappropriately recorded. CONCLUSIONS: These results demonstrate that motion in and around an MR scanner can induce EMI significant enough to be misinterpreted by implanted PMs and ICDs leading to inappropriate changes in therapy. These findings highlight that PM or ICDs, including MR-conditional systems should not enter the MRI room, except in case of an examination under specified conditions.

A telemonitoring platform for the investigation of blood pressure profiles in pacemaker patients.

Rate responsive pacemakers (PM) use different strategies to adapt the patient paced rate, with the aim of having the best hemodynamic performance in response to internal or external conditions. Closed-loop stimulation (CLS) uses intracardiac impedance as a sensor principle. The evaluation of impact of different pacing modalities and technologies on the blood pressure (BP) profiles is mainly investigated in short-term laboratory settings, mainly due to the need of reliable daily-based BP values. The impact of CLS pacing on systemic blood pressure (BP) has been studied on short term basis, but data on long term effects are scarse. This study present a telemedicine platform designed for evaluating the effect of the rate responsive technology on daily systolic and diastolic BP data. BP and pacemaker data were collected daily from fourteen patients during a 3 month period. The total number of monitoring days was 1277 (91 day/patient), for a total number of 4455 BP measures. On average 3.5 measure/day/patient were received). The analysis of the BP data showed that CLS pacing results in diastolic pressure closer to the normal values than accelerometer-based pacing, which were associated to lower diastolic pressures.

Che-1 modulates the decision between cell cycle arrest and apoptosis by its binding to p53.

The tumor suppressor p53 is mainly involved in the transcriptional regulation of a large number of growth-arrest- and apoptosis-related genes. However, a clear understanding of which factor/s influences the choice between these two opposing p53-dependent outcomes remains largely elusive. We have previously described that in response to DNA damage, the RNA polymerase II-binding protein Che-1/AATF transcriptionally activates p53. Here, we show that Che-1 binds directly to p53. This interaction essentially occurs in the first hours of DNA damage, whereas it is lost when cells undergo apoptosis in response to posttranscriptional modifications. Moreover, Che-1 sits in a ternary complex with p53 and the oncosuppressor Brca1. Accordingly, our analysis of genome-wide chromatin occupancy by p53 revealed that p53/Che1 interaction results in preferential transactivation of growth arrest p53 target genes over its pro-apoptotic target genes. Notably, exposure of Che-1(+/-) mice to ionizing radiations resulted in enhanced apoptosis of thymocytes, compared with WT mice. These results confirm Che-1 as an important regulator of p53 activity and suggest Che-1 to be a promising yet attractive drug target for cancer therapy.

Cellular and Kaposi's sarcoma-associated herpes virus microRNAs in sepsis and surgical trauma.

Once a patient is in septic shock, survival rates drop by 7.6% for every hour of delay in antibiotic therapy. Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and triage. Here, we study the potential roles of a panel of cellular and viral miRNAs as sepsis biomarkers. We performed genome-wide microRNA (miRNA) expression profiling in leukocytes from septic patients and nonseptic controls, combined with quantitative RT-PCR in plasmas from two cohorts of septic patients, two cohorts of nonseptic surgical patients and healthy volunteers. Enzyme-linked immunosorbent assay, miRNA transfection and chromatin immunoprecipitation were used to study the effects of Kaposi sarcoma herpes virus (KSHV) miRNAs on interleukin's secretion. Differences related to sepsis etiology were noted for plasma levels of 10 cellular and 2 KSHV miRNAs (miR-K-10b and miR-K-12-12*) between septic and nonseptic patients. All the sepsis groups had high KSHV miRNAs levels compared with controls; Afro-American patients had higher levels of KSHV-miR-K12-12* than non-Afro-American patients. Both KSHV miRNAs were increased on postoperative day 1, but returned to baseline on day 7; they acted as direct agonists of Toll-like receptor 8 (TLR8), which might explain the increased secretion of the IL-6 and IL-10. Cellular and KSHV miRNAs are differentially expressed in sepsis and early postsurgical patients and may be exploited for diagnostic and therapeutic purposes. Increased miR-K-10b and miR-K12-12* are functionally involved in sepsis as agonists of TLR8, forming a positive feedback that may lead to cytokine dysregulation.

An optically coupled system for quantitative monitoring of MRI gradient currents induced into endocardial leads.

The time-varying gradient fields generated during Magnetic Resonance Imaging (MRI) procedures have the potential to induce electrical current on implanted endocardial leads. Whether this current can result in undesired cardiac stimulation is unknown. This paper presents an optically coupled system with the potential to quantitatively measure the currents induced by the gradient fields into endocardial leads during MRI procedures. Our system is based on a microcontroller that works as analog-to-digital (A/D) converter and sends the current signal acquired from the lead to an optical high-speed light-emitting-diode transmitter. Plastic fiber guides the light outside the MRI chamber, to a photodiode receiver and then to an acquisition board connected to a PC. The preliminary characterization of the performances of the system is also presented.

Setups for in vitro assessment of RFID interference on pacemakers.

The aim of this study is to propose setups for in vitro assessment of RFID (radiofrequency identification) interference on pacemakers (PM). The voltage induced at the input stage of the PM by low-frequency (LF) and high-frequency (HF) RFID transmitters has been used to quantify the amount of the interference. A commercial PM was modified in order to measure the voltage at its input stage when exposed to a sinusoidal signal at 125 kHz and 13.56 MHz. At both frequencies, two antennas with different dimensions (diameter = 10 cm and 30 cm, respectively) were used to generate the interfering field, and the induced voltage was measured between the lead tip and the PM case (unipolar voltage), and between the tip and ring electrodes (bipolar voltage). The typical lead configurations adopted in similar studies or proposed by international standards, as well as lead paths closer to actual physiological implants were tested. At 125 kHz, the worst-case condition differs for the two antennas: the 10 cm antenna induced the highest voltage in the two-loop spiral configuration, whereas the 30 cm antenna in the 225 cm(2) loop configuration. At 13.56 MHz, the highest voltage was observed for both the antennas in the 225 cm(2) loop configuration. Bipolar voltages were found to be lower than the unipolar voltages induced in the same configurations, this difference being not as high as one could expect from theoretical considerations. The worst-case scenario, in terms of the induced voltage at the PM input stage, has been identified both for LF and HF readers, and for two sizes of transmitting antennas. These findings may provide the basis for the definition of a standard implant configuration and a lead path to test the EMI effects of LF and HF RFID transmitters on active implantable devices.

Electromagnetic compatibility of WLAN adapters with life-supporting medical devices.

This paper investigates the electromagnetic compatibility of 45 critical care medical devices (infusion pumps, defibrillators, monitors, lung ventilators, anesthesia machines and external pacemakers) with various types of wireless local area network (WLAN, IEEE 802.11 b/g, 2.45 GHz, 100 mW) adapters. Interference is evaluated by performing ad-hoc tests according to the ANSI C63.18 recommended practice. The behavior of the devices during the tests was monitored using patient simulators/device testers specific for each device class. Electromagnetic interference cases were observed in three of 45 devices at a maximum distance of 5 cm. In two cases the interference caused malfunctions that may have clinical consequences for the patient. The authors' findings show that the use of these wireless local area network adapters can be considered reasonably safe, although interference may occur if they are operated at very close distance (<10 cm) to the medical devices.

[Endoscopic therapy with balloon dilatation in patients with colonic post anastomotic strictures. Personal experience]. / Trattamento endoscopico con dilatazione pneumatica nei pazienti affetti da stenosi coliche post-anastomotiche. Esperienza personale.

BACKGROUND AND AIM: Colorectal post anastomotic benign strictures are not uncommon. The purpose of this study was to investigate the results of endoscopic balloon dilatation of anastomotic strictures. MATERIALS AND METHODS: The study was on a retrospective survey. Records of 14 consecutive patients with anastomotic strictures (5 F, 9 M; median age 64 years; range: 50-87 years), attending our GI Unit from February 1st 2008 to December 31st 2009, were analyzed. All patients had been operated for colon carcinoma. All of them were treated with balloon dilatation. RESULTS: All the patients presented symptoms of obstruction. The total number of dilatation sessions was 37 and the median number of sessions by patient was 1,5 (range: 1-7). After the procedures, all patients had an improvement of symptoms. No complications were observed. CONCLUSIONS: Our experience underlines that endoscopic ballon dilatation, in patients with post anastomotic benign strictures, is a safe technique with a low rate of complications.

Percutaneous endoscopic gastrostomy (PEG) in critically ill patients performed at bed in Intensive Care Unit: report of our experience.

BACKGROUND AND AIM: Patients with severe brain injures and severe neurological diseases frequently require prolonged nutritional support during their hospitalization as well as during their rehabilitation period. Since 1980, the percutaneous endoscopic gastrostomy (PEG) has become the method of choice for long term feeding. The aim of the present study was to present our experience concerning the placement of PEG in critically ill patients, recovered in Intensive Care Unit (ICU). MATERIALS AND METHODS: From 3-05-2001 to 28-09-2005, 36 patients (13 female, 23 male) with a median age of 63 years [range: 18-86 years], recovered in ICU of the Sandro Pertini Hospital, underwent PEG. These patients were retrospectively evaluated in terms of complications, indications to the procedures, durability of gastrostomy and mortality. Intravenous antibiotic prophylaxis was administered 1 h before the procedure (ceftriaxone 2gr). The entire PEG was placed in ICU at patient's bed, with the assistance of the anaesthetist. Propofol was used e.v. for sedation and fentanest for analgesia while lidocaine was used for local anesthesia. A 16-Fr or 20-Fr tube was inserted by the "pull method", after a complete upper gastroduodenoscopy. RESULTS: PEG was performed mainly for neurological disorders including cerebrovascular accidents (13), SLA (8), post-traumatic coma (7), post-cardiac arrest coma (7) and dementia (1). Procedure related mortality was 0%. The tube was changed in 4 patients due to clogging. The durability of the tube was a median of 2 months (range: 1-12 months). In 23 patients the placement of the PEG was definitive. CONCLUSIONS: Our experience underlines that PEG, in selected critically ill patients, is a safe technique easy to perform even in ICU.

Bouveret's syndrome: description of a case.

Bouveret's syndrome is a rare condition usually caused by a single large stone impacted in the duodenum. This is a cause of gastric outlet. Even if endoscopy is the mainstay of diagnosis, the radiographic examinations are also important too. Generally, the stones are too large to be removed endoscopically. Conservative endoscopic treatment should be attempted initially, and if it fails, surgical approach should be performed.

[Diagnosis and treatment of bleeding peptic ulcer: our experience]. / Diagnosi e trattamento dell'ulcera peptica emorragica. Nostra esperienza.

BACKGROUND: Bleeding peptic ulcer (PU) is the commonest cause of an acute upper gastrointestinal bleed. Aim of this study was to present our data regard the management of acute bleeding from PU during urgent endoscopy (examination performed in 2-6 h by the call). MATERIALS AND METHODS: This study is based on an observational retrospective protocol. Records of 259 consecutive patients with PU (92 F, 167 M; median age 71.5 years; range: 19-100 years), attending our GI Unit from February 1st 2004 to July 31st 2007, were analyzed. RESULTS: Out of 259 patients with PU, 170 (65.6%) were treated with endoscopic hemostasis followed by medical therapy (PPI 80 mg bolus within 12 h of endoscopy followed by 8 mg/for 72 h and then an oral PPI , 40 mg once daily for 30 days), while 89 (34.4%) patients received only medical therapy (PPI, 40 mg once daily for 30 days). All ulcerative lesions with endoscopic stigmata of acute bleeding, visible vessels or adherent clot (Forrest Ia-IIb) were treated during the gastroscopy. The endoscopic procedures used were: injection of 1:10000 adrenaline (about 10 mL) around the bleeding lesion in 93 cases (55%); injection therapy and thermal method (argon plasma coagulation) in 53 cases (31%); injection therapy and mechanical method (metallic clips) in 20 cases (12%); only mechanical method (metallic clips) in 4 cases (2%). Endoscopic hemostasis was achieved in 251 pts (97%), while 17 pts (6.5%) required second endoscopy for rebleeding. Three patients (1.16%) required immediate surgery for failure of primary endoscopic hemostasis. The mortality within 30 days from the bleeding episode was 3.9% (10 pts). CONCLUSIONS: The treatment of this condition has made important progress since the introduction of emergency endoscopy and endoscopic techniques for hemostasis. The application of specific protocols, significantly decreases rebleeding and the need for surgery, whereas mortality is still high. Our data are in keeping with previous studies of the literature.

[Sedation with propofol in endoscopic retrograde cholangiopancreatography: personal experience]. / La sedazione profonda con propofol in corso di colangiopancreatografia retrograda endoscopica: esperienza personale.

AIM: Adequate sedation is fundamental for the execution of the endoscopic retrograde cholangiopancreatography (ERCP). Propofol is widely used for gastrointestinal endoscopy because of its rapid recovery profile. The aim of this study was to determine, retrospectively, whether the administration of propofol was safe in patients undergoing ERCP, both diagnostic and therapeutic. MATERIALS AND METHODS: In our GI Unit, from 1st February 2006 to 23 November 2006, we performed 100 ERCP. All the patients were sedated by using midazolam e.v., as pre-anaesthetic agent, and propofol e.v. During the procedure, vital signs were continuously monitored (oxygen saturation, blood pressure, heart rate). Patients were also divided into two groups: less than 80 years of age (group I) and 80 years of age and older (group II). Cardiorespiratory complications were recorded. RESULTS: Patients were 51 females and 49 males, with a median age of 74 years (range: 23-94 years). Group I was composed by 72 patients (35 F, 37 M) and Group II by 28 patients (16 F, 12 M). There were no episodes of hemodynamic instability or airway obstruction. New ECG changes (1 ischemia, 3 arrhythmias) and 1 significant oxygen desaturation episode (SpO2<90%) occurred in 5% of procedures. If we considered the two groups, the rates of cardiopulmonary complications were 4.1% and 7.1%, respectively in group I and in group II. CONCLUSIONS: Propofol seems to be safe and effective sedation for ERCP, with a low complication rate, also in patients aged 80 years or older.

Radiofrequency dosimetry in subjects implanted with metallic straight wires: a numerical study.

A numerical study to investigate the effects of the exposure to electromagnetic fields (EMF) at 900 and 1800 MHz on biological tissues implanted with thin metallic structures has been carried out, using the finite difference time domain (FDTD) solution technique. The results of the model show that the presence of a metallic wire yields to a significant increase in the local specific energy absorption rate (SAR). The present standards and/or guidelines on safe exposures of humans to EMF does not cover persons with implanted devices and thus the threshold levels to define safe exposure conditions might not apply in presence of high SAR gradients, such as the ones generated by thin metallic implanted objects. However, exposure to EMF fields below the actual safe levels even in presence of thin conductive structures cause rather low temperature rises (1 degrees C).

Electromagnetic interference to infusion pumps. Update2008 from GSM mobile phones.

Electromagnetic interference (EMI) to critical care medical devices has been reported by various groups. Previuos study demonstrated that infusion pumps are susceptible of false alarm buzzing and block of infusion, when exposed to various EMI sources. Aim of this paper is to investigate the changes in the risk of EMI from the estimates of our previous 2005 survey and to extend the EMI risk assessment to newer telecommunication products: DECT phones and WiFi terminals. With regards to GSM phones, compare to the results obtained in 2005, we observed a decrease in the rate of failure (from 58% to 30%). From our findings, the use of WiFi and DECT does not pose a real risk to infusion systems.

[Distal hyperplastic polyps as a marker for advanced neoplasm of the proximal colon. Our experience]. / Il polipo iperplastico distale come marcatore di neoplasia colica avanzata prossimale. La nostra esperienza.

BACKGROUND AND AIM: While, several studies indicate that there is an association between proximal and distal colorectal adenomas, no agreement seems to be between the presence of distal hyperplastic polyps and proximal neoplasia. The aim of this study was to investigate, retrospectively, the possible correlation between the distal hyperplastic polyps and proximal colorectal neoplasia. MATERIALS AND METHODS: In our GI Unit, from 1st February 2006 to 24 November 2006, we performed 142 polypectomy. Patients were 36 females and 80 males, with a median age of 66 years [range: 38-87 years]. All of the polpys were resected during colonoscopy and sent for histological study. Chi-square test was used for statistical analysis. A probability value of P< or =0.05 was considered to be statistically significant. RESULTS: Histological study showed the following results: 33 hyperplastic polyps (8 F, 21 M; median age 63 years), 100 adenomas (26 F, 61 M; median age 67 years) and 2 inflammatory polpys (2 F, 0 M; median age 71 years). The rectal localization was associated with a significantly higher frequency of hyperplastic polyps (63.6% vs 23.5%), OR: 5.688 (95% C.I. 2.445-13.230) (p<0.0001). Five hyperplastic polyps of the rectum were associated with 5 adenomas located 1 in the rectum, 2 in the sigmoid colon, and 1 in the descendens colon and 1 in the ascendens colon. While, 5 adenomas were associated with 5 adenocarcinoma. CONCLUSIONS: Guidelines from the American College of Gastroenterology and the American Society of Gastrointestinal Endoscopy do not recommend colonoscopy for patients with distal hyperplastic polyps. Also our study is in keeping with the data of the literature and it confirmed that rectal localization is associated with a higher prevalence of hyperplastic polyps.

[Foreign bodies in the upper gastrointestinal tract. Personal experience]. / Corpi estranei del tratto digestivo superiore. Esperienza personale.

OBJECTIVE: Foreign bodies ingestion is a potentially serious problem. The majority of ingested foreign bodies pass spontaneously, but serious complications, such as bowel perforation and obstruction, can occur. In the present work, we report our experience in the management of ingested foreign bodies. MATERIALS AND METHODS: The study was observational and retrospective. We included in the study the foreign bodies ingestions occurred during urgent endoscopy (examination performed from 1 to 6 h by the call). RESULTS: Records of 696 consecutive EGDS performed in urgency at the Unit of Gastroenterology and Digestive Endoscopy of the Hospital Sandro Pertini of Rome, from 01-02-'04 to 18-01-2006, were analyzed retrospectively. Out of these procedures, 21 (3.01%) were performed for suspected foreign bodies ingestion. CONCLUSIONS: We present the initial report of our working experience. Objects that have passed the duodenum should be managed conservatively by radiographic surveillance and inspection of stool. Endoscopic or surgical approach is indicated when significant symptoms develop or if the object fails to progress through the gastrointestinal tract. The present data are in keeping with previous studies of the literature.

Temperature and SAR measurement errors in the evaluation of metallic linear structures heating during MRI using fluoroptic probes.

The purpose of this work is to evaluate the error associated with temperature and SAR measurements using fluoroptic temperature probes on pacemaker (PM) leads during magnetic resonance imaging (MRI). We performed temperature measurements on pacemaker leads, excited with a 25, 64, and 128 MHz current. The PM lead tip heating was measured with a fluoroptic thermometer (Luxtron, Model 3100, USA). Different contact configurations between the pigmented portion of the temperature probe and the PM lead tip were investigated to find the contact position minimizing the temperature and SAR underestimation. A computer model was used to estimate the error made by fluoroptic probes in temperature and SAR measurement. The transversal contact of the pigmented portion of the temperature probe and the PM lead tip minimizes the underestimation for temperature and SAR. This contact position also has the lowest temperature and SAR error. For other contact positions, the maximum temperature error can be as high as -45%, whereas the maximum SAR error can be as high as -54%. MRI heating evaluations with temperature probes should use a contact position minimizing the maximum error, need to be accompanied by a thorough uncertainty budget and the temperature and SAR errors should be specified.

Placement of two overlapping uncovered metallic stents for malignant gastric outlet and duodenal obstruction due to colon cancer.

Malignant obstruction of the gastric outlet and duodenum is frequently due to extrinsic involvement by tumors from contiguous organs, in particular from pancreas and gallbladder. The treatment of malignant gastroduodenal stenoses is difficult. Many patients have advanced malignant disease and are too ill to undergo surgical approach. Surgical gastrojejunostomy has been considered the palliative treatment of choice. Metallic stents can be useful in this condition with adequate palliation obtained in most cases. We report a case in which self-expanding metallic stents were placed for stenoses of the gastric outlet and duodenum due to a colon cancer.

Morphological analysis of P-wave in patients prone to atrial fibrillation.

Aim of this study was to present a P-wave model, based on a linear combination of Gaussian functions, to quantify morphological aspects of Pwave in patients prone to atrial fibrillation. Five minutes ECG recordings were performed in 25 patients with permanent dual chamber pacemakers set at 40/min in order to have spontaneous beats. ECG signals were acquired using a 32-lead mapping system for high-resolution biopotential measurement (ActiveTwo, Biosemi, The Netherlands, sample frequency 2 kHz, 24 bit resolution). Four healthy subjects were also recorded as a control group. Up to 8 Gaussian models have been computed for each averaged P-wave extracted from every lead. The P-wave morphology is then evaluated by the following parameters: best model orders @ degrees of freedom adjusted R-square (AdjRsq) =97.5%; minimum (sigmamin) and maximum (sigmamax) standard deviation of the Gaussians included in the model, number of relative maxima and minima (max+min), and zeroes of the fit. Significant differences in the best model order were obtained between the control group and patients group. Accordingly, the number of relative maxima and minima was higher in the patient group. These parameters might all be markers of the fractionated electrical activity that characterizes paroxysmal AF patients in sinus rhythm.