An Efficient Procedure to Compensate for the Errors Due to the Probe Mispositioning in a Cylindrical Near-Field Facility.

This paper deals with the compensation of the probe mispositioning errors occurring in a cylindrical near-field (NF) facility due to the imprecise control of the linear and azimuthal positioners allowing the cylindrical scanning and/or to their limited resolution and to defects in the rails guiding the linear motion. As a result, 3-D errors in the positioning of the probe at any sampling point, as prescribed by the adopted non-redundant representation, affect the accuracy of the NF measurements. An efficient procedure is here proposed to properly compensate for these errors. It involves two steps. The former allows one to correct the mispositioning errors due to the deviation of each actual sampling point from the nominal measurement cylinder. The latter makes use of an iterative technique to restore the NF samples at any sampling point fixed by the used non-redundant representation from the ones obtained at the previous step and affected by 2-D mispositioning errors. Once these steps have been fruitfully applied, the so-compensated NF samples are effectively interpolated through a 2-D optimal sampling interpolation (OSI) formula to accurately reconstruct the input data required to perform the traditional cylindrical near-to-far-field transformation. The OSI representation is here developed by considering an elongated antenna under test as enclosed either in a prolate spheroid or in a cylinder terminated by two half spheres (rounded cylinder) in order to make the representation effectively non-redundant. Numerical test results, which thoroughly prove the efficacy of the devised procedure in correcting even severe 3-D mispositioning errors, are reported.

An Effective Near-Field to Far-Field Transformation with Planar Spiral Scanning for Flat Antennas under Test.

The goal of this article is to provide numerical and experimental assessments of an effective near-field to far-field transformation (NF-FF T) technique with planar spiral scanning for flat antennas under test (AUTs), which requires a non-redundant, i.e., minimum, number of NF measurements. This technique has its roots in the theory of non-redundant sampling representations of electromagnetic fields and was devised by suitably applying the unified theory of spiral scans for non-volumetric antennas to the case in which the considered AUT is modeled by a circular disk having its radius equal to half of the AUT's maximum dimension. It makes use of a 2D optimal sampling interpolation (OSI) formula to accurately determine the massive amount of NF data required by the classical plane-rectangular NF-FF T technique from the non-redundant data gathered along the spiral. It must be emphasized that, when considering flat AUTs, the developed transformation allows one to further and significantly save measurement time as compared to that required by the previously developed NF-FF T techniques with planar spiral scans based on a quasi-planar antenna modeling, because the number of turns of the spiral and that of NF data to be acquired depend somewhat on the area of the modeling surface. The reported numerical simulations assess the accuracy of the proposed NF-FF T technique, whereas the experimental tests prove its practical feasibility.

Reconstruction of the Far-Field Pattern of Volumetric AUTs from a Reduced Set of Near-Field Samples Collected along a Planar Spiral with a Uniform Step.

An efficient near-to-far-field transformation (NTFFT) technique, wherein the near-field (NF) measurements are acquired along a planar spiral with a uniform step to make the control of the involved positioners easier, is developed in this article. Such a technique is tailored for quasi-spherical, i.e., volumetric, antennas under test and makes use of a reduced number of NF data. An effective two-dimensional sampling interpolation algorithm, allowing the accurate reconstruction of the input NF data for the standard NTFFT with plane-rectangular scan, is obtained by setting the spiral step equal to the sample spacing required for interpolating along a radial line according to the spatial bandlimitation properties of electromagnetic fields, and by properly developing a non-redundant representation along such a spiral. Tests results are reported to demonstrate that the proposed NTFFT technique retains the same accuracy as the standard plane-rectangular one.

Long-term outcome of prosthetic joint infections treated with two-stage revision.

Long-term evaluation of prosthetic joint infection treated with two-stage revision. Retrospective analysis of 102 periprosthetic infections treated with two-stage revision from 2010 to 2012 in Albenga hospital, Italy. During the second stage, samples for microbiological tests were collected. Failure was defined as a persistence of infection during the second stage or as a relapse during follow-up. 102 cases (55 hip, 47 knee) were analyzed. Patients were evaluated for a median of 44 months. 8/102 (8%) had positive cultures at replacement. These patients were treated with long-term antibiotic treatment and in 3/8 (38%) infection was cured. 9 patients were loss to follow-up or died, 6 patients (6%) had a relapse a median of 16,3 months from replanting. Risk factors significantly related to failures were diabetes and infection due to methicillin-resistant staphylococci. Two stage revision requires continued follow up. Screening for infection at replacement suggests prolonged antibiotic treatment.

Therapeutic management of chronic hepatitis B in clinical practice: a region-wide survey.

GOALS: To characterize the clinical and treatment pattern in a large population of hepatitis B virus (HBV) patients managed at tertiary referral centers in clinical practice. BACKGROUND: Successful treatment, either with interferon (IFN) or nucleos(t)ide analogs (NUCs), of chronic HBV infection is associated with improved long-term patient outcome. However, in clinical practice, the actual management of these patients is not well characterized, and data regarding treatment pattern in this setting are lacking. METHODS: In this cross-sectional study, we evaluated 505 patients chronically infected with HBV alone and who had at least 1-year follow-up. We assessed indication to, rate of, and type of treatment as well as the characteristics of treated patients. RESULTS: Overall prevalence of positivity for HBe antigen was 19.3%, and the majority of patients had chronic hepatitis (47.5%). Non-Italian patients represented approximately one third of the population (27.1%). Among patients with indication to antiviral therapy (n=318), treatment was actually carried out in 264 patients (83.0%), prevalently with NUCs (65.9%). IFN-treated patients were younger (P<0.001), more frequently male (P=0.025) and HBeAg positive (P=0.003), and less frequently cirrhotics (P<0.001) as compared with patients treated with NUCs. CONCLUSIONS: In a geographical area with a low positivity for HBe antigen, antiviral therapy is actually carried out in the majority of patients who have indication to treatment, prevalently with NUCs, whereas IFN treatment is more frequently carried out in young, HBe antigen-positive patients who do not have advanced liver disease.

Varied spectrum of clinical presentation and mortality in a prospective registry of visceral leishmaniasis in a low endemicity area of Northern Italy.

BACKGROUND: Visceral Leishmaniasis (VL) is endemic in 88 countries, in areas of relatively low incidence with a relevant proportion of immune suppressed patients clinical presentation, diagnosis and management may present difficulties and pitfalls. METHODS: Demographic data, clinical, laboratory features and therapeutic findings were recorded in patients identified by a regional VL disease registry from January 2007 to December 2010. RESULTS: A total of 55 patients (36 adults mean age 48.7 years, 19 children median age 37.5 months) were observed presenting with 65 episodes. All childen were immunocompetent, whereas adults affected by VL included both immunocompetent (n°17) and immunesuppressed (n°19) patients. The clinical presentation was homogeneous in children with predominance of fever and hepato-splenomegaly. A wider spectrum of clinical presentations was observed in immunocompromised adults. Bone marrow detection of intracellular parasites (Giemsa staining) and serology (IFAT) were the most frequently used diagnostic tools. In addition, detection of urinary antigen was used in adult patients with good specificity (90%). Liposomal amphotericin B was the most frequently prescribed first line drug (98.2% of cases) with 100% clinical cure. VL relapses (n°10) represented a crucial finding: they occurred only in adult patients, mainly in immunocompromised patients (40% of HIV, 22% of non-HIV immunocompromised patients, 5,9% of immunocompetent patients). Furthermore, three deaths with VL were reported, all occurring in relapsing immunocompromised patients accounting for a still high overall mortality in this group (15.8%). CONCLUSIONS: The wide spectrum of clinical presentation in immunesuppresed patients and high recurrence rates still represent a clinical challenge accounting for high mortality. Early clinical identification and satisfactory treatment performance with liposomal amphotericin B are confirmed in areas with low-level endemicity and good clinical standards. VL needs continuing attention in endemic areas where increasing numbers of immunocompromised patients at risk are dwelling.

Vertebral osteomyelitis due to Lactobacillus paracasei in a diabetic patient. A case report and literature review.

Staphylococci are the most frequent cause of vertebral osteomyelitis, but infections due to unusual pathogens are also reported. We describe a rare case of spondylodiscitis due to Lactobacillus paracasei. A 74-year-old diabetic male was evaluated for fever and back pain. Blood cultures and vertebral biopsy were positive for Lactobacillus paracasei. He often took laxatives and probiotics for chronic constipation. After target treatment the patient improved but he died for a heart attack two months after the end of the treatment. Although Lactobacillus paracasei is usually not pathogenic, sepsis is described in immunocompromised patients while vertebral osteomyelitis is rare.

Neutralizing monoclonal antibodies for the prevention of severe COVID-19: a retrospective study during Omicron BA.1 variant surge.

Among treatment options for Coronavirus disease 2019 (COVID-19), monoclonal antibodies (mAbs) showed to be effective in preventing disease progression, but real-world data during the Omicron variant surge are still lacking. Multicentre retrospective study evaluating the effectiveness of sotrovimab and casirivimab-imdevimab in fragile patients with mild SARS-CoV-2 infection between November 2021 and March 2022. Unfavourable outcome was defined as increased need for oxygen supplementation and/or death. Of 268 study-participants, 12 (4.48%) previously needed supplemental oxygen, while 6 (2.24%) had active solid neoplasia (2.24%); 186 (69%) have previously received SARS-CoV-2 vaccination. Overall, 22 (8%) had unfavourable outcomes (42% versus 6% of patients with and without previous oxygen need and 50% versus 7% of patients with and without active solid neoplasia). Both supplemental oxygen therapy before SARS-CoV-2 infection and solid malignant tumour have shown to be risk factors for treatment failure. Log-rank test did not identify differences between sotrovimab and casirivimab-imdevimab treatment. Despite diffusion of Omicron variant, the rate of unfavourable outcome was higher than expected. The presence of underlying risk factors, including solid cancer and previous oxygen therapy are independently associated with risk of COVID-19 progression, suggesting the need for antiviral treatments not limited to mAbs and implementation of vaccine campaign.

COVID-19 6 months after hospital discharge: pulmonary function impairment and its heterogeneity.

After 6 months, about half of #COVID19 discharged subjects present impaired respiratory function with exertional dyspnoea, mainly due a reduced CO diffusion (34%), followed by pulmonary restriction (19%) https://bit.ly/3vcnbdR.

Effective bowel cleansing before colonoscopy: a randomized study of split-dosage versus non-split dosage regimens of high-volume versus low-volume polyethylene glycol solutions.

BACKGROUND: Adequate bowel cleansing is essential for a high-quality, effective, and safe colonoscopy. OBJECTIVES: To evaluate the degree of colon cleansing comparing split-dosage versus non-split-dosage intake of two different polyethylene glycol (PEG) volumes (low-volume PEG + ascorbic acid vs standard-volume PEG-electrolyte solution) and to identify predictors of poor bowel cleansing. DESIGN: Single-blind, active control, randomized study. SETTING: Tertiary-care institutions in Italy. PATIENTS: This study involved adult patients undergoing elective colonoscopy. INTERVENTION: Colonoscopy with different bowel preparation methods. MAIN OUTCOME MEASUREMENTS: Degree of bowel cleansing. RESULTS: We randomized 895 patients, and 868 patients were finally included in intention-to-treat (ITT) analysis. Overall compliance was excellent (97%) for both preparation methods. No difference in tolerability was recorded. Palatability was superior with low volume compared with high volume (acceptable or good 58% vs 51%, respectively, P < .005), independently of intake schedule. PEG plus ascorbic acid produced the same degree of cleansing as standard-volume PEG-electrolyte solution (77% vs 73.4%, respectively, within the split-dosage group and 41.7% vs 44.3%, respectively, within the non-split-dosage group). Independently of PEG volumes, the split-dosage regimen produced markedly superior cleansing results over the same-day method (good/excellent 327/435, 75.2% vs 186/433, 43.0%, P = .00001). Maximum cleansing was observed in colonoscopies performed within 8 hours from the last fluid intake versus over 8 hours from the last fluid intake (P < .001). The degree of bowel cleansing affected both cecal intubation (failed intubation 11.7% with fair/poor preparation vs 1.2% with good/excellent preparation, P = .00001) and polyp detection rates (12.2% with fair/poor vs 24.6% with good/excellent preparation, P = .001). Aborted procedures were significantly more frequent in the non-split-dosage arm (21.2% vs 6.9%, odds ratio [OR] 3.60 [2.29-5.77], P < .0001). Independent predictors of poor bowel cleansing were male sex (OR 1.45 [1.08-1.96], P = .014) and a non-split-dosage bowel preparation schedule (OR 2.08 [1.89-2.37], P = .0001). CONCLUSION: Low-volume PEG plus ascorbic acid is as effective as high-volume PEG-electrolyte solution but has superior palatability. A split-dosage schedule is the most effective bowel cleansing method. Colonoscopy should be performed within 8 hours of the last fluid intake.

Qualitative Alpha-defensin Versus The Main Available Tests For The Diagnosis Of Periprosthetic Joint Infection: Best Predictor Test?

Introduction: Biomarkers such as α-defensin demonstrated to be a potentially useful option in periprosthetic joint infection (PJI) diagnosis. Recently, a new point-of-care test for α-defensin level detection in synovial fluid has been commercialized in Europe. The aim of this study is to compare the α-defensin test (SynovasureTM) diagnostic ability with the main available clinical tests for periprosthetic joint infection diagnosis in a practical clinical setting of a Bone Infection Unit. Methods: Between 2015 and 2017, 146 patients with suspected chronic PJI were screened with SynovasureTM. Seventy-three of these met the Musculoskeletal Infection Society (MSIS) criteria and were included in the analysis. According to MSIS criteria, 40 patients (54.7%) were classified as infected and 33 (45.3%) as not infected. The results obtained with SynovasureTM were recorded and compared with standard diagnostic methods for PJI diagnosis. Results: SynovasureTM showed a sensitivity of 85.0 % (95% CI 70.2 to 94.3) and a specificity of 96.9 % (95% CI 83.8 to 99.9) for PJI detection. The positive likelihood ratio of SynovasureTM was 27.2 (95% CI 3.9 to 188.1) and the negative likelihood ratio was 0.2 (95% CI 0.1 to 0.3). The diagnostic odds ratio was 181.3 (95% CI 20.7 to 1590.4). SynovasureTM demonstrated a statistical significant difference when compared to Erythrocyte Sedimentation Rate (ESR) and C-reactive Protein (CRP) specificity (at least one positive test) and preoperative culture sensitivity (1 positive culture). Conclusion: Our findings show that SynovasureTM sensitivity is lower than quantitative α-D test, but when compared to the main available tests shows a good specificity and the highest DOR. On the SF it is the easier test to do, due to the fact that it needs a minimal amount of SF and it is not limited by blood contamination or antibiotic use. Whereas there is no single standalone test, SynovasureTM should be considered a reliable additional test for periprosthetic joint infection diagnosis in everyday clinical practice.

The peroneus brevis flap in the treatment of bone infections of the lower limb.

The Peroneus Brevis Flap is a described option for the soft tissue coverage and for small bone gap reconstruction in the lower third of the lower leg, where few other local flaps are available and reliable. We analysed retrospectively a case series of 11 consecutive patients whose age ranged from 31 to 87 years (mean 56), who underwent a reconstruction with a PB flap in the treatment of post-traumatic bone infections from October 2010 to February 2012. In our series, only one patient at a 3 year minimum follow-up showed recurrence of the bone infection and required further surgical treatment. Main complications were partial flap necrosis or overlying skin graft necrosis, but without the need of secondary surgery. In our experience, the PB flap is a reliable option for soft tissue coverage in the treatment of distal leg and ankle osteomyelitis.

Azole-resistant Candida albicans prosthetic joint infection treated with prolonged administration of anidulafungin and two-stage exchange with implant of a mega-prosthesis.

Fungal prosthetic joint infection (PJI) is a rare but severe complication of artroplasty. We report a case of PJI due to azole-resistant Candida albicans successfully treated with combination of prolonged administration of anidulafungin and two-stage joint exchange with insertion of a mega-prosthesis.

[Diagnosis in patients with a painful arthroplasty]. / Diagnosi differenziale in pazienti con protesi ortopedica dolorosa.

The differential diagnosis between asepting loosening or prosthetic joint infection is not always easy. Tc-99m-labelled leucocyte scans, frozen section and histology can help recognise doubtful cases. We report the experience of the Unit for Infectious Diseases and Septic Orthopaedics of the ASL-2 Liguria, Italy, with a Tc-99m-labelled leucocyte scan and intraoperative frozen section to choose the best therapeutic approach: one-stage or two-stage exchange or arthrodesis-arthroplastica. All cases underwent histology and intraoperative cultures to confirm the diagnosis, and the effectiveness of the approach was evaluated at follow up after 18 months. From January 2011 to December 2012, 36 patients were evaluated (21 hip and 15 knee arthroprosthesis). The Tc-99m-labelled leukocyte scan was positive in 31 and negative in 5 patients. Frozen section was negative in 7 patients. Five of them were patients with a negative Tc-99m-labelled leucocyte scan and were treated successfully with one-stage exchange, even if, in one of them, Enterococcus faecalis was isolated at replacement and suppressive antibiotic treatment was needed. The other 31 patients were treated with arthrodesis arthroplasty (3 patients) or a two-stage exchange. In this group the Tc-99m-labelled leucocyte scan was positive in all patients and the frozen section was positive in 29/31 cases with 6% false negative. Histology was positive in 27/31 with 13% of false negative. The sensitivity and specificity value was respectively 90% and 100% in the frozen section, 84% and 100% in histology. Cultures were positive in 23/31 cases. Patients subjected to two-stage exchange were evaluated again during prosthesis replacement but the results of the Tc-99m-labelled leucocyte scan and histology showed unclear results more frequently: the Tc-99m-labelled leucocyte scan was positive in two cases, the frozen section in three and histology in seven in spite of positive culture in three cases and one relapse in a patient with a frozen section and histology positive but negative culture. In the second step sensitivity and specificity were respectively 67% and 96% in the frozen section, 75% and 88% in histology. Finally, our experience suggests the utility of nuclear and histological tests during diagnostic work-up for differential diagnosis of aseptic loosening or prosthetic joint infection. The same tests produce more uncertain data when performed in two-stage exchange during the second step.

[Non-tubercular vertebral osteomyelitis: diagnosis and therapy of 45 patients from a single Italian centre]. / Spondilodisciti non tubercolari: valutazione prospettica di 45 pazienti seguiti presso un unico.

AIM OF THE STUDY: to evaluate the episodes of non-tubercular spondylodiskitis diagnosed between 1998 and 2002 at the Ospedale S. Corona, Pietra Ligure (SV). METHODS: perspective evaluation of vertebral osteomyelitis classified as spontaneous or iatrogenic if associated with procedures on the spinal cord, with detection of associated risk factors, localization, aetiology and treatment. RESULTS: 45 episodes, 71% spontaneous and 29% iatrogenic were observed. Associated risk factors were present in 47% of spontaneous spondylodiskitis. Lumbosacral localization was detected in 68% of spontaneous and 100% of iatrogenic episodes. Other localizations in spontaneous spondylodiskitis were dorsal (25%) or cervical (7%). Methicillin-sensitive staphylococci caused the majority of spontaneous spondylodiskitis, while methicillin-resistant strains were more frequently involved in iatrogenic episodes. Among spontaneous spondylodiskitis, 63% healed with antibiotics for 8 weeks, but surgery was often needed in dorsal localizations. In iatrogenic forms antibacterial therapy for 8 weeks-6 months was effective in cases not associated with foreign bodies but their presence always required surgery for healing. CONCLUSIONS: spondylodiskitis is more frequently localized at lumbosacral level. Beta-lactams are generally effective in spontaneous episodes, while iatrogenic ones often require associations of drugs. Surgery may be required in the case of dorsal localization or in the presence of foreign bodies.

[Non-tubercular vertebral osteomyelitis: diagnosis and therapy of 45 patients from a single Italian centre]. / Non-tubercular vertebral osteomyelitis: diagnosis and therapy of 45 patients from a single Italian centre.

AIM OF THE STUDY: to evaluate the episodes of non-tubercular spondylodiskitis diagnosed between 1998 and 2002 at Ospedale S. Corona, Pietra Ligure (SV). METHODS: prospective evaluation of vertebral osteomyelitis classified as spontaneous or iatrogenic if associated with procedures on the spinal cord, with detection of associated risk factors, localization, etiology and treatment. RESULTS: 45 episodes, 71% spontaneous and 29% iatrogenic were observed. Associated risk factors were present in 47% of spontaneous spondylodiskitis. Lumbosacral localization was detected in 68% of spontaneous and 100% of iatrogenic episodes. Other localizations in spontaneous spondylodiskitis were dorsal (25%) or cervical (7%). Methicillin-sensitive staphylococci caused the majority of spontaneous spondylodiskitis, while methicillin-resistant strains were more frequently involved in iatrogenic episodes. Among spontaneous spondylodiskitis, 63% healed with antibiotics for 8 weeks, but surgery was often needed in dorsal localizations. In iatrogenic forms antibacterial therapy for 8 weeks-6 months was effective in cases not associated with foreign bodies but their presence always required surgery for healing. CONCLUSIONS: spondylodiskitis is more frequently localized at the lumbosacral level. Beta-lactams are generally effective in spontaneous episodes, while iatrogenic episodes often require associations of drugs. Surgery may be required in the case of dorsal localization or in the presence of foreign bodies.

Prosthetic joint infections due to Mycobacterium tuberculosis: A report of 5 cases.

INTRODUCTION: Tubercular infection of prosthetic joint arthroplasty is sporadically described, but its incidence is rising. Misdiagnosis is common because of disparate clinical presentation. PRESENTATION OF CASE: We describe 1 hand, 2 hip and 2 knee prosthetic-joint infections due to Mycobacterium tuberculosis in patients without a previous history of tuberculosis. All of them were initially misdiagnosed as bacterial infections and unsuccessfully treated with antibiotic for a long period of time. Diagnosis was made by means of culture of periprosthetic tissues and histolopathological examination. Tuberculosis was cured in all patients, but two of them have had a permanent functional damage (one arthrodesis of the knee and one loss of hand function). DISCUSSION: An aggressive diagnostic approach is required to make diagnosis of periprosthetic tubercular infection. The identification of the pathogen is advisable to test drug susceptibility. CONCLUSION: The low index of suspicion of periprosthetic tubercular infection could delay a correct diagnosis with risk of permanent damage due to a late treatment. During any surgical revision of prosthetic joints with suspect infection culture for tuberculosis should be taken into consideration.