Search

Lung ultrasound (LUS) has rapidly emerged in COVID-19 diagnosis and for the follow-up during the acute phase. LUS is not yet used routinely in lung damage follow-up after COVID-19 infection. We investigated the correlation between LUS score, and clinical and laboratory parameters of severity of SARS-COV-2 damage during hospitalization and at follow-up visit. Observational retrospective study including all the patients discharged from the COVID-19 wards, who attended the post-COVID outpatient clinic of the IRCCS Policlinico San Matteo in April-June 2020. 115 patients were enrolled. Follow-up visits with LUS score measurements were at a median of 38 days (IQR 28-48) after discharge. LUS scores were associated with the length of hospitalization (p 0.001), patients' age (p = 0.036), use of non-invasive ventilation (CPAP p 0.001 or HFNC p = 0.018), administration of corticosteroids therapy (p = 0.030), and laboratory parameters during the acute phase (WBC p 0.001, LDH p 0.001, CRP p 0.001, D-dimer p = 0.008, IL-6 p = 0.045), and inversely correlated with lymphocyte count (p = 0.007). We found correlation between LUS score and both LDH (p = 0.001) and the antibody anti-SARS-CoV-2 titers (p value = 0.008). Most of these finding were confirmed by dichothomizing the LUS score (≤ 9 or 9 points). We found a significantly higher LUS score at the follow-up in the patients with persistent dyspnea (7.00, IQR 3.00-11.00) when compared to eupnoeic patients (3.00, IQR 0-7.00 p 0.001). LUS score at follow-up visit correlates with more severe lung disease. These findings support the hypothesis that ultrasound could be a valid tool in the follow-up medium-term COVID-19 lung damage.

Hydroxychloroquine was widely used during the severe acute respiratory syndrome coronavirus 2 pandemic as an antiviral drug. Most previous pharmacokinetic/pharmacodynamic studies on hydroxychloroquine were conducted on healthy volunteers or patients receiving long-term therapy. There are no studies on the elimination of hydroxychloroquine after short-term treatments. Hydroxychloroquine is known to have a pro-arrhythmic effect through QT interval prolongation, but data in this setting are not conclusive. Our aims were to estimate the time needed for hydroxychloroquine concentrations (CWe collected blood samples and electrocardiograms of patients who underwent short-term therapy with hydroxychloroquine during drug intake and after discontinuation. Hydroxychloroquine concentrations were determined by high-performance liquid chromatography-tandem mass spectrometry and analysed with a linear regression model to estimate the elimination time of the drug after its discontinuation. We conducted a multivariate analysis of the corrected QT interval correlation with COur data suggest that short-term hydroxychloroquine courses can generate significant CThe study confirms the long half-life of hydroxychloroquine and its effect on the corrected QT interval even after short-term courses of the drug. This can inform the clinician using hydroxychloroquine treatments that it would be safer to start or re-initiate treatments with corrected QT interval-prolonging potential 16 days after hydroxychloroquine discontinuation.

Objectives More than a year has passed since the initial outbreak of SARS-CoV-2, which caused many hospitalizations worldwide due to COVID-19 pneumonia and its complications. However, there is still a lack of information detailing short- and long-term outcomes of previously hospitalized patients. The purpose of this study is to analyze the most frequent lung CT findings in recovered COVID-19 patients at mid-term follow-ups. Methods A total of 407 consecutive COVID-19 patients who were admitted to the Fondazione IRCCS Policlinico San Matteo, Pavia and discharged between February 27, 2020, and June 26, 2020 were recruited into this study. Out of these patients, a subset of 108 patients who presented with residual asthenia and dyspnea at discharge, altered spirometric data, positive lung ultrasound and positive chest X-ray was subsequently selected, and was scheduled to undergo a mid-term chest CT study, which was evaluated for specific lung alterations and morphological patterns. Results The most frequently observed lung CT alterations, in order of frequency, were ground-glass opacities (81%), linear opacities (74%), bronchiolectases (64.81%), and reticular opacities (63.88%). The most common morphological pattern was the non-specific interstitial pneumonia pattern (63.88%). Features consistent with pulmonary fibrosis were observed in 32 patients (29.62%). Conclusions Our work showed that recovered COVID-19 patients who were hospitalized and who exhibited residual symptoms after discharge had a slow radiological recovery with persistent residual lung alterations. Advances in knowledge This slow recovery process should be kept in mind when determining the follow-up phases in order to improve the long-term management of patients affected by COVID-19.

Purpose Recently, some attempts have been made to integrate lung ultrasound (LUS) teaching into medical curricula. However, current education studies of LUS are extremely heterogeneous due to the lack of evidence-based guidelines on LUS education. In particular, the assessment of competencies is poorly standardized and mostly relies on non-validated scales. A new validated tool, the objective structured assessment of lung ultrasound skills (LUS-OSAUS), has the potential to overcome these limitations. Therefore, we adopted the LUS-OSAUS tool to assess the competencies of a group of LUS-trained undergraduates. Existing no prior practical applications of the LUS-OSAUS, our aim was to investigate the practical utility of this tool and its applicability in the evaluation of US-trained medical students. Methods Eight undergraduates (two males, six females) were enrolled on a voluntary basis to receive a theoretical and practical training in LUS. Once completed their training, each student performed an LUS examination on a different patient hospitalized for respiratory symptoms. The same eight patients were also scanned by a senior resident in emergency medicine for a comparison with students’ results. Students and the senior resident were tested by an examiner using the LUS-OSAUS tool. We compared the scores obtained by operators in all areas of competence of the LUS-OSAUS, the total scores, and the time needed to complete the sonographic task. Results Median students’ score in the single items of the scale was significantly lower than the ones obtained by the senior resident (4.0 [3.3–5.0] vs. 5.0 [5.0–5.0]; p

This paper proposes the architecture of the hash accelerator, developed in the framework of the European Processor Initiative. The proposed circuit supports all the SHA2 and SHA-3 operative modes and is to be one of the hardware cryptographic accelerators within the crypto-tile of the European Processor Initiative. The accelerator has been verified on a Stratix IV FPGA and then synthesised on the Artisan 7 nanometres TSMC silicon technology, obtaining throughputs higher than 50 Gbps for the SHA2 and 230 Gbps for the SHA-3, with complexity ranging from 15 to about 30 kGE and estimated power dissipation of about 13 (SHA2) to 26 (SHA-3) mW (supply voltage 0.75 V). The proposed design demonstrates absolute performances beyond the state-of-the-art and efficiency aligned with it. One of the main contributions is that this is the first SHA-2 SHA-3 accelerator synthesised on such advanced technology.

Following the expansion of the industry requiring small satellites with payloads producing high data rates, the Consultative Committee for Space Data Systems (CCSDS) introduced the CCSDS 131.2-B-1 standard in 2012. The standard combines Serially Concatenated Convolutional Codes (SCCC) with different types of modulation to provide a cost-effective, reliable and efficient payload data transmitter with a high degree of flexibility. This flexibility, due to the number of modulation and coding formats (ModCod), can help designers to better adapt the system configuration to the specific needs of the target. In addition, the use of Adaptive Code and Modulation (ACM) provides the means to adapt payload data transmission to variable channel conditions. To further increase flexibility, the ”EGRET - Next Generation High Rate Telemetry” project has recently defined a proposal to extend the CCSDS SCCC standard to include more efficient transmission schemes. This extension, also called SCCC-X, introduces 10 new ModCods together with a new SCCC-BCH combined encoder and new higher-order modulations (128-APSK and 256-APSK). This document illustrates the entire transmission chain architecture of the SCCC-X telemetry transmitter, highlighting the possible design trade-offs in order to provide a reference for other future developers. Special attention is paid to the analysis of implementation compromises in terms of Bit Error Rate (BER) loss, efficiency, throughput, and source occupation on relevant space-grade FPGAs. In particular, the synthesis results show that SCCC-X can be implemented without changes in the critical path compared to CCSDS 131.2-B-1 and that the implementations are able to achieve more than 450MSym/s on the Xilinx Space-Grade Kintex 7 Ultrascale FPGA and more than 250Msym/s on the Microsemi RTG4 FPGA.

In the context of growing the adoption of advanced sensors and systems for active vehicle safety and driver assistance, an increasingly important issue is the security of the information exchanged between the different sub-systems of the vehicle. Random number generation is crucial in modern encryption and security applications as it is a critical task from the point of view of the robustness of the security chain. Random numbers are in fact used to generate the encryption keys to be used for ciphers. Consequently, any weakness in the key generation process can potentially leak information that can be used to breach even the strongest cipher. This paper presents the architecture of a high performance Random Number Generator (RNG) IP-core, in particular a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) IP-core, a digital hardware accelerator for random numbers generation which can be employed for cryptographically secure applications. The specifications used to develop the proposed project were derived from dedicated literature and standards. Subsequently, specific architecture optimizations were studied to achieve better timing performance and very high throughput values. The IP-core has been validated thanks to the official NIST Statistical Test Suite, in order to evaluate the degree of randomness of the numbers generated in output. Finally the CSPRNG IP-core has been characterized on relevant Field Programmable Gate Array (FPGA) and ASIC standard-cell technologies.

Random numbers are widely employed in cryptography and security applications, and they represent one of the main aspects to take care of along a security chain. They are employed for creation of encryption keys, and if generation process is weak, the whole chain can be compromised: weaknesses could be exploited to retrieve the key, thus breaking even the strongest cipher. This paper presents the architecture of a digital Random Number Generator (RNG) IP-core to be employed as hardware accelerator for cryptographically secure applications. Such design has been developed starting from specifications based on literature and standards, and in order to assess the randomness degree of generated output, it has been successfully validated through the official NIST Statistical Test Suite. Finally the RNG IP-core has been characterized on Field Programmable Gate Array (FPGA) and ASIC standard-cell technologies: on Intel Stratix IV FPGA it offers a throughput of 720 Mbps requiring up to 6000 Adaptive Logic Modules, while on 45 nm it reaches a throughput of 4 Gbps with a complexity of 119 kGE.

Acute kidney injury (AKI) is emerging as a predictor of poor stroke outcome, however, it is often not recognized. The aim of our study was to evaluate post-stroke AKI burden, AKI risk factors and their influence in post-stroke outcome. From 2013 to 2016, 440 individuals with stroke diagnosis admitted in Stroke Unit, Foundation IRCCS Policlinico San Matteo (Pavia, Italy), were retrospectively enrolled. AKI cases identified by KDIGO criteria through the electronic database and hospital chart review were compared with the ones reported in discharge letters or in administrative hospital data base. Mortality data were provided by Agenzia Tutela della Salute of Pavia. We included 430 patients in the analysis. Median follow-up was 19.2 months. We identified 79 AKI cases (18% of the enrolled patients, 92% classified as AKI stage 1), a fivefold higher number of cases than the ones reported at discharge. 37 patients had AKI at the admission in the hospital, while 42 developed AKI during the hospitalization. Cardioembolic (p = 0.01) and hemorrhagic (p = 0.01) stroke types were associated with higher AKI risk. Admission National Institutes of Health Stroke Scale (NIHSS, p

Summary Background: The TOAST study estimates that 34% of ischaemic strokes are of undetermined aetiology. Improvements in the diagnosis of the pathogenetic mechanism of ischaemic stroke would translate into a better care, in analogy to other fields of vascular and internal medicine. Objective: To measure the reduction of undetermined aetiology strokes performing a set of additional diagnostic tests. Design: Consecutive case series with historical controls. Setting: Internal Medicine Ward with a stroke area (SA) admitting most stroke patients of a large hospital in Italy. Subjects: A total of 179 ischaemic stroke patients admitted to SA in 2004–2005 compared with 105 ischaemic stroke patients admitted to the whole department in 2001. Intervention: To perform more diagnostic tests, including transesophageal echocardiography (TEE), in the greatest possible number of ischaemic stroke inpatients admitted in SA of the Internal Medicine Department, in the years 2004–2005. Results: More diagnostic tests were performed during the study period than in 2001, especially TEE (56% of patients in 2004–2005 vs. 3% of patients in 2001). We observed a significant reduction of undetermined aetiology from 38% in 2001 to 16% in 2004–2005 (p

We evaluated a simplified algorithm for safely postponing diagnostic imaging for pulmonary embolism (PE). At the index visit, patients were identified as being at high or low risk of PE; the former received full dosage low molecular weight heparin while the latter were left untreated until performance of diagnostic imaging (max 72 hours). During this period, no thromboembolic events occurred in low-risk patients (0/211, 0.% [upper 95% CI 0.9%]); only one event occurred in those at high-risk (1/125, 0.8% [upper 95% CI, 1.2]). Our study demonstrates that diagnostic imaging for PE can be safely deferred for up to 3 days.

The continuous increase in complexity in automotive electronics has led to cars that include up to 80 Electronic Control Units (ECUs). As a consequence, in-car networks are currently up to their limit in terms of data load, flexibility and bandwidth. The Ethernet backbone is thus considered as the best performing solution. On the other hand, the growing interconnection of cars with the external world requires high security standards in order to prevent safety risks for car passengers. The IEEE 802.1AE MAC Security Standard (MACSec) solves the security issues of Ethernet networks by providing confidentiality, authenticity and integrity of data. This paper presents an efficient hardware implementation of the MACSec standard for the automotive world. The system was synthesized on a Stratix V FPGA and on a 28nm standard-cell CMOS technology. In terms of maximum throughput, the FPGA results in 1.1 Gbps while the standard-cell technology reaches 3.9 Gbps. The FPGA implementation occupies 4.5% of the Adaptive Logic Modules (ALMs) while the standard-cell one gives a 285 kgate size. The proposed architecture represents a suitable implementation for a low area and high-performance solution as usually required by in-car network controllers.

Objective To determine the presence of early carotid atherosclerosis and associated risk factors in patients with juvenile-onset systemic lupus erythematosus (SLE). Methods The carotid intima–media wall thickness (IMT) was measured by B-mode ultrasound in patients with SLE onset before the age of 16 years and in sex- and age-matched healthy control subjects. Risk factors for atherosclerosis were determined at the time of the ultrasound scan and included traditional cardiovascular and SLE-related risk factors. Results Twenty-six patients with juvenile-onset SLE and 26 healthy controls were studied. The mean (±SD) IMT of the SLE patients was significantly higher than that of the control group (0.57 ± 0.05 mm and 0.54 ± 0.03 mm, respectively; P = 0.006). The results of IMT measurement were not correlated with the patients' age, disease duration, SLE Disease Activity Index (SLEDAI) score, Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index (DI) score, laboratory indicators of lupus activity, or cumulative prednisone dose. Patients with nephrotic-range (NR) proteinuria (≥3.5 gm/24 hours; n = 6) had a significantly higher IMT than did those without (n = 20) (P = 0.02). Patients with NR proteinuria also had significantly higher SLEDAI scores, SLICC/ACR DI scores, and systolic and diastolic blood pressures, and significantly higher levels of total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and fibrinogen. No difference in any of the above variables, including the IMT, was observed when SLE patients without NR proteinuria were compared with healthy controls. Conclusion These patients with juvenile-onset SLE had ultrasonographic evidence of premature atherosclerosis. The risk of early atherosclerosis may be higher in patients with NR proteinuria.

ISPRA and Tuscany Region Administration recently funded a project aimed at assessing and mapping landslide hazard of the area of the n. 250 “Castelnuovo di Garfagnana” map (1:50,000 scale). The area includes the upper Serchio River basin (Tuscany, Italy) and exhibits peculiar geological and geomorphological features and severe climatic conditions, which cause high landslide hazard. The project proceeded as follows: 1:10,000 geomorphological survey and landslide inventory map; Physical and mechanical properties of rocks (discontinuities, strength, rock mass classification) and soils (grain size, consistency); GIS oriented organization of the spatial distribution of the considered factors; GIS supported statistical analysis (spatial analysis, conditional and multivariate analyses, neural network technique); Landslide hazard map, where landslide hazard is subdivided into five classes based on instability probability; Final products: landslide hazard map at 1:50,000 scale, together with other related maps (landslide map, structural sketch, geotechnical sketch, isohyet map, etc.); explaining booklet; database.

The proposed experimental study is aimed at contributing to the landslide susceptibility evaluation using a multidisciplinary approach: geological, geomorphological and geo-engineering survey, together with multivariate statistical analysis and GIS technique. It is included in a wider research project, aimed at defining the landslide hazard in the area of the map no. 250 “Castelnuovo di Garfagnana” (1:50 000 scale). This study is based on the realization of a landslides inventory map and statistical data analysis using probabilistic methods. The methodology applied in ranking slope instability proceeded step by step. At first, geomorphologic investigation was performed in order to realize a landslide inventory map. A GIS database was created to collect the characteristics related to landslides geometry, type of movement and state of activity. Geo-engineering survey and characterization with in situ and laboratory tests allowed assessing Rock Mass Classification and geotechnical properties of soils (texture and consistency). The statistical approach for evaluating the landslide susceptibility is based on the assumption that the landslide probability for the currently landslides-free areas could be evaluated studying the conditions which led to past and present instability. A set of environmental factors, thought to be related to landslides, were analysed and their spatial distribution organized in different layers. Then, GIS-supported spatial analysis, conditional and multivariate analysis, allowed to calculate the connections between instability factors and landslide distribution. This step evolved towards two distinct statistical methods, both indirect and quantitative, leading to a classification of the land surface in some different susceptibility domains. Conditional analysis was applied to a particular type of terrain unit named Unique Condition Unit (UCU) that is a unique combination of the instability factors. The computer-aided evaluation of the landslide index within each UCU represents the probability of landslide occurrence, according to Bayes statistical concept. Multivariate analysis was applied to the same set of instability factors, but to a different type of terrain unit, the grid cell. The results showed a quantitative response, more reliable about the effectiveness of each instability factors, with the possibility of verifying their statistical significance.

Background. Management of patients with suspected Pulmonary Embolism (PE) is problematic if diagnostic imaging is not available. Pretest Clinical Probability (PCP) and D-dimer (D-d) assessment were shown to be useful to identify those high risk patients for whom empirical, protective anticoagulation is indicated (Siragusa S et al. Arch Intern Med2004;164:2477–82). Objective of the study. In consecutive patients with suspected PE, we evaluated whether PCP and D-d assessment, together with the use of low molecular weight heparins (LMWHs), allow objective appraisal of PE to be deferred for up to 72 hours. Methods. In case of deferment of diagnostic imaging for PE, patients identified at high-risk (those with high PCP and those with moderate PCP and a positive D-d), received a protective full-dose treatment of LMWH; the remaining patients were discharged without anticoagulants. All patients were scheduled to undergo objective tests for PE (ventilation/perfusion lung scanning or computed tomography lung scan) within 72 hours from the index visit (figure). Standard antithrombotic therapy was then administered when diagnostic tests confirmed Venous ThromboEmbolism (VTE). Results. 336 patients with suspected PE were included in this study. The prevalence of VTE was 6.1% (95% CI 2.7–9.3) in the “low-risk group” and 50.4% (95% CI 41.7–59.1) in the “high-risk group”. In total, VTE was confirmed in 76 (22.6%) of 336 patients (95% CI 18.2–27). Patients’ characteristics, median time for deferral test and for LMWH administration are listed in table 1. Events at the short-term (72 hours) and long-term follow-up are listed in table 2. None of the patients had major bleeding events during the follow-ups. Conclusions. When objective diagnostic assessment of PE is not immediately available, management of symptomatic PE patients can prove highly unsatisfactory. This study demonstrates that a simple and reproducible approach allows a safe deferral of diagnostic imaging for PE for up to 72 hours. patients’ characteristics Baseline features Low risk group (n. 211) High-risk group (n. 125) p value n.s.: not significant Age in years (range) 59.3 (22–91) 60.3 (23–91) n.s. Sex (F/M) 98/113 59/66 n.s. Time since onset of symptoms (days) 1.7 1.5 n.s. Co-morbidity and 16 (7.5) 25 (19.2) 0.03 Median time of deferral test (hours) 49.5 42.5 n.s. Median time of protective anticoagulation (hours) not applicable 35.5 not applicable Outcome of Short- and Long-term FU Categories of patients (n) Events at the short-term FU Events at the long -term FU* FU indicates follow-up; CI indicates Confidence Intervals. *This refers to patients in whom Pulmonary Embolism has been previously ruled out (n. 260). “Low-risk group” (211) 0 (0%) [95% CI 1.4] 0 (0%) [95% CI 1.4] “High-risk group” (125) 1 (0.8%) [95% CI 2.3] 3 (2.4%) [95% CI 3.2] Patients clinically suspected of PE without immediate availability of diagnostic tests Patients clinically suspected of PE without immediate availability of diagnostic tests

The recovery of vanadium from heavy oil fly ash having a high carbon content was performed using a four-step process consisting of a preliminary burning in order to reduce the carbonaceous fraction, followed by an acid leaching and an oxidative precipitation of vanadium pentoxide. The preliminary burning was conducted in the temperature range 650 to 1150 °C, below the initial deformation temperature (IDT) of the fly ash. The temperature of the preliminary burning step was revealed to be a significant parameter. Above 950 °C various phenomena (fusion, volatilisation of V, formation of V–Ni refractory compounds) occurred that adversely affected the recovery of vanadium. The burning temperature of 850 °C was found to be the best as a result of the trade-off between the overall vanadium recovery yield (83%) and the V2O5 weight percentage in the precipitate (84.8%).

Enhanced LDL oxidation in uremic patients: An additional mechanism for accelerated atherosclerosis? Since oxidized low-density lipoprotein (LDL) is more atherogenic than native LDL, LDL oxidation was investigated in uremic patients who often develop accelerated atherogenesis. Three groups of uremic patients were studied (10 on predialysis conservative therapy, 11 on repetitive hemodialysis, 13 on peritoneal dialysis) and compared with seventy matched controls. LDL oxidation was evaluated in all patients as: (i) the susceptibility to in vitro oxidation (by measuring the resistence to Cu ++ -induced formation of conjugated dienes), (ii) vitamin E concentration in LDL, and (iii) presence of plasma anti-oxidized LDL antibodies, expressed as the ratio anti-oxLDL/anti-nativeLDL antibodies. The lipid profile was studied in all patients. Vitamin E concentration did not differ between the various groups, although LDL from uremic patients appeared more susceptible to in vitro and in vivo oxidation (as demonstrated by an earlier generation of conjugated dienes and by the presence of an higher antibody ratio) compared to control subjects. Subclass analysis of the different patients revealed that peritoneal dialysis treatment ameliorated the oxidation markers. However, a prolonged dialytic treatment caused a decrease in vitamin E concentration in LDL and increased their susceptibility to oxidation.

To investigate the occurrence of enhanced low-density lipoprotein (LDL) oxidation as an additional factor promoting atherosclerosis progression in hypertensive patients.The oxidation of plasma LDL was investigated in a group of untreated patients with mild-to-moderate essential hypertension without clinically evident target organ damage and in a group of control subjects.LDL oxidation was evaluated as both the susceptibility to oxidation in vitro and the presence of plasma anti-oxidized LDL antibodies (as an index for oxidation in vivo).LDL from hypertensive subjects exhibited enhanced susceptibility to oxidation in vitro as revealed by early and accelerated generation of conjugated dienes after exposure to CuSO4. Vitamin E concentration in LDL from hypertensive subjects was slightly but significantly decreased and its efficiency in protecting LDL from oxidation was impaired. Furthermore, a higher plasma anti-oxidized LDL titre was found in hypertensive patients. Subclass analysis revealed that the contemporary presence of hypercholesterolaemia did not significantly modify either the increased susceptibility of LDL to oxidation or the presence of plasma anti-oxidized LDL antibodies detected in hypertensive patients. Moreover, no correlation was found between LDL oxidation parameters and blood pressure values.LDL from hypertensive patients is more susceptible to oxidation in vitro and is more promptly oxidized in vivo. These findings suggest a possible participation of LDL oxidation in promoting and accelerating the atherosclerosis that often develops in hypertensive patients.

Background: Treatment of patients with suspected deep vein thrombosis (DVT) or pulmonary embolism (PE) is problematic if diagnostic imaging is not immediately available. Pretest clinical probability (PCP) and D-dimer assessment can be used to identify patients for whom empirical protective anticoagulation is indicated. To evaluate whether PCP and D-dimer assessment, together with the use of low-molecular-weight heparins (LMWHs), allow objective appraisal of DVT and PE to be deferred for up to 72 hours, patients with suspected DVT and PE were prospectively examined. Methods: Patients identified with a high PCP or a moderate PCP with positive D-dimer test results received a protective full-dose treatment of LMWH; the remaining patients were discharged without anticoagulant administration. However, all patients were scheduled to undergo objective tests for DVT or PE within 72 hours. Standard antithrombotic therapy was administered when deferred diagnostic tests confirmed venous thromboembolism. Results: In total, 409 consecutive patients with suspected DVT and 124 with suspected PE were included in this study. A total of 23.8% (95% confidence interval [CI], 20.3%-27.3%) of patients had confirmed venous thromboembolism. At the short-term follow-up (72 hours), only a single thromboembolic event (0.2%; upper 95% CI, 0.6%) had occurred, whereas at the 3-month follow-up, 5 events (1.2%; 95% CI, 0.2%-2.1%) had occurred in patients in whom diagnosis of DVT or PE had previously been ruled out. None of the patients had major bleeding events. Ninety percent of patients were treated as outpatients. Conclusion: Our study demonstrates that this approach allows the safe deferral of diagnostic procedures for DVT and PE for up to 72 hours.

Sir—In their report, M Ruggeri and colleagues (Feb 10, p 441) point out the clinical relevance of the congenital absence of the inferior vena cava (IVC) in young patients (

The genetic structure of 126 Ethiopian and 139 Senegalese Y chromosomes was investigated by a hierarchical analysis of 30 diagnostic biallelic markers selected from the worldwide Y-chromosome genealogy. The present study reveals that (1) only the Ethiopians share with the Khoisan the deepest human Y-chromosome clades (the African-specific Groups I and II) but with a repertoire of very different haplotypes; (2) most of the Ethiopians and virtually all the Senegalese belong to Group III, whose precursor is believed to be involved in the first migration out of Africa; and (3) the Ethiopian Y chromosomes that fall into Groups VI, VIII, and IX may be explained by back migrations from Asia. The first observation confirms the ancestral affinity between the Ethiopians and the Khoisan, which has previously been suggested by both archaeological and genetic findings.