Evaluation of junctional zone differential and ratio as possible markers of clinical efficacy in uterine artery embolisation of adenomyosis.

BACKGROUND: Uterine artery embolisation is a recommended method of adenomyosis treatment with good clinical results. Changes in uterine volume and maximal junctional zone thickness (JZmax) after embolisation are thoroughly analyzed in the literature. In contrast changes in other suggested morphological diagnostic markers of adenomyosis (junctional zone differential / JZdiff-and junctional zone ratio / JZratio) are rarely evaluated. This single-centre retrospective study aimed to analyse the changes in morphological parameters used for the MR imaging diagnosis of adenomyosis (including JZdiff and JZratio) after UAE. Clinical effectiveness and safety were also analysed. MATERIALS AND METHODS: Patients who underwent UAE for pure adenomyosis from Jan 2008 to Dec 2021 were evaluated. Adenomyosis was diagnosed based on JZmax, JZdiff, and JZratio measured on MR imaging. To assess clinical efficacy, the numerical-analog-quality-of-life (QoL) score was routinely obtained from patients at our centre. MRI morphological data were analysed. Statistical analysis was conducted using Wilcoxon signed-rank test, uni- and multivariate regression models, Pearson product-moment correlation, and Kruskal-Wallis tests. RESULTS: From our database of 801 patients who underwent UAE between Jan 2008 to Dec 2021, preprocedural MR images were available in 577 cases and, 15 patients had pure adenomyosis (15/577, 2.6%). Uterine volume, JZmax, and JZdiff decreased significantly after UAE; QoL score increased significantly. A significant correlation was found between QoL change vs. JZmax and JZdiff change. Permanent amenorrhoea and elective hysterectomy 5 years after UAE were both 7.1%. CONCLUSION: Change of JZdiff after UAE in adenomyosis is a potential marker of clinical success. UAE is a clinically safe and effective treatment for adenomyosis.

Observation of Interatomic Coulombic Decay Induced by Double Excitation of Helium in Nanodroplets.

Interatomic Coulombic decay (ICD) plays a crucial role in weakly bound complexes exposed to intense or high-energy radiation. So far, neutral or ionic atoms or molecules have been prepared in singly excited electron or hole states that can transfer energy to neighboring centers and cause ionization and radiation damage. Here we demonstrate that a doubly excited atom, despite its extremely short lifetime, can decay by ICD; evidenced by high-resolution photoelectron spectra of He nanodroplets excited to the 2s2p+ state. We find that ICD proceeds by relaxation into excited He^{*}He^{+} atom-pair states, in agreement with calculations. The ability of inducing ICD by resonant excitation far above the single-ionization threshold opens opportunities for controlling radiation damage to a high degree of element specificity and spectral selectivity.

Efficient Indirect Interatomic Coulombic Decay Induced by Photoelectron Impact Excitation in Large Pure Helium Nanodroplets.

Ionization of matter by energetic radiation generally causes complex secondary reactions that are hard to decipher. Using large helium nanodroplets irradiated by extreme ultraviolet (XUV) photons, we show that the full chain of processes ensuing primary photoionization can be tracked in detail by means of high-resolution electron spectroscopy. We find that elastic and inelastic scattering of photoelectrons efficiently induces interatomic Coulombic decay (ICD) in the droplets. This type of indirect ICD even becomes the dominant process of electron emission in nearly the entire XUV range in large droplets with radius ≳40 nm. Indirect ICD processes induced by electron scattering likely play an important role in other condensed-phase systems exposed to ionizing radiation as well, including biological matter.

Relaxation dynamics in excited helium nanodroplets probed with high resolution, time-resolved photoelectron spectroscopy.

Superfluid helium nanodroplets are often considered as transparent and chemically inert nanometer-sized cryo-matrices for high-resolution or time-resolved spectroscopy of embedded molecules and clusters. On the other hand, when the helium nanodroplets are resonantly excited with XUV radiation, a multitude of ultrafast processes are initiated, such as relaxation into metastable states, formation of nanoscopic bubbles or excimers, and autoionization channels generating low-energy free electrons. Here, we discuss the full spectrum of ultrafast relaxation processes observed when helium nanodroplets are electronically excited. In particular, we perform an in-depth study of the relaxation dynamics occurring in the lowest 1s2s and 1s2p droplet bands using high resolution, time-resolved photoelectron spectroscopy. The simplified excitation scheme and improved resolution allow us to identify the relaxation into metastable triplet and excimer states even when exciting below the droplets' autoionization threshold, unobserved in previous studies.

Tissue attenuation imaging and tissue scatter imaging for quantitative ultrasound evaluation of hepatic steatosis.

We aimed to assess the feasibility of ultrasound-based tissue attenuation imaging (TAI) and tissue scatter distribution imaging (TSI) for quantification of liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD). We prospectively enrolled 101 participants with suspected NAFLD. The TAI and TSI measurements of the liver were performed with a Samsung RS85 Prestige ultrasound system. Based on the magnetic resonance imaging proton density fat fraction (MRI-PDFF), patients were divided into ≤5%, 5-10%, and ≥10% of MRI-PDFF groups. We determined the correlation between TAI, TSI, and MRI-PDFF and used multiple linear regression analysis to identify any association with clinical variables. The diagnostic performance of TAI, TSI was determined based on the area under the receiver operating characteristic curve (AUC). The intraclass correlation coefficient (ICC) was calculated to assess interobserver reliability. Both TAI (rs = 0.78, P < .001) and TSI (rs = 0.68, P < .001) showed significant correlation with MRI-PDFF. TAI overperformed TSI in the detection of both ≥5% MRI-PDFF (AUC = 0.89 vs 0.87) and ≥10% (AUC = 0.93 vs 0.86). MRI-PDFF proved to be an independent predictor of TAI (ß = 1.03; P < .001), while both MRI-PDFF (ß = 50.9; P < .001) and liver stiffness (ß = -0.86; P < .001) were independent predictors of TSI. Interobserver analysis showed excellent reproducibility of TAI (ICC = 0.95) and moderate reproducibility of TSI (ICC = 0.73). TAI and TSI could be used successfully to diagnose and estimate the severity of hepatic steatosis in routine clinical practice.

Effectiveness of PD-(L)1 inhibitors alone or in combination with platinum-doublet chemotherapy in first-line (1L) non-squamous non-small-cell lung cancer (Nsq-NSCLC) with PD-L1-high expression using real-world data.

BACKGROUND: Anti-programmed cell death protein (death-ligand) 1 [PD-(L)1] therapy alone [cancer immunotherapy (CIT)-mono] or combined with platinum-based chemotherapy (CIT-chemo) is used as the first-line treatment for patients with metastatic non-small-cell lung cancer (NSCLC). Our study compared clinical outcomes with CIT-mono versus CIT-chemo in the specific clinical scenario of non-squamous (Nsq)-NSCLC with a high PD-L1 expression of ≥50% [tumor proportion score (TPS) or tumor cells (TC)]. METHODS: This was a retrospective cohort study using a real-world de-identified database. Patients with metastatic Nsq-NSCLC with high PD-L1 expression initiating first-line CIT-mono or CIT-chemo between 24 October 2016 and 28 February 2019 were followed up until 28 February 2020. We compared overall survival (OS) and real-world progression-free survival (rwPFS) using the Kaplan-Meier methodology. Hazard ratios (HRs) were adjusted (aHR) for differences in baseline key prognostic characteristics using the inverse probability of treatment weighting methodology. RESULTS: Patients with PD-L1-high Nsq-NSCLC treated with CIT-mono (n = 351) were older and less often presented with de novo stage IV disease than patients treated with CIT-chemo (n = 169). With a median follow-up of 19.9 months for CIT-chemo versus 23.5 months for CIT-mono, median OS and rwPFS did not differ between the two groups [median OS: CIT-chemo, 21.0 months versus CIT-mono, 22.1 months, aHR = 1.03, 95% confidence interval (CI) 0.77-1.39, P = 0.83; median rwPFS: CIT-chemo, 10.8 months versus CIT-mono, 11.5 months, aHR = 1.04, 95% CI 0.78-1.37, P = 0.81]. CIT-chemo showed significant and meaningful improvement in OS and rwPFS versus CIT-mono only in the never-smoker subgroup, albeit among a small sample of patients (n = 50; OS HR = 0.25, 95% CI 0.07-0.83, interaction P = 0.02; rwPFS HR = 0.40, 95% CI 0.17-0.95, interaction P = 0.04). CONCLUSION: Except in the subgroup of never-smoker patients, sparing the chemotherapy in first-line CIT treatment does not appear to impact survival outcomes in Nsq-NSCLC patients with high PD-L1 expression.

Diagnosis of focal liver lesions with deep learning-based multi-channel analysis of hepatocyte-specific contrast-enhanced magnetic resonance imaging.

BACKGROUND: The nature of input data is an essential factor when training neural networks. Research concerning magnetic resonance imaging (MRI)-based diagnosis of liver tumors using deep learning has been rapidly advancing. Still, evidence to support the utilization of multi-dimensional and multi-parametric image data is lacking. Due to higher information content, three-dimensional input should presumably result in higher classification precision. Also, the differentiation between focal liver lesions (FLLs) can only be plausible with simultaneous analysis of multi-sequence MRI images. AIM: To compare diagnostic efficiency of two-dimensional (2D) and three-dimensional (3D)-densely connected convolutional neural networks (DenseNet) for FLLs on multi-sequence MRI. METHODS: We retrospectively collected T2-weighted, gadoxetate disodium-enhanced arterial phase, portal venous phase, and hepatobiliary phase MRI scans from patients with focal nodular hyperplasia (FNH), hepatocellular carcinomas (HCC) or liver metastases (MET). Our search identified 71 FNH, 69 HCC and 76 MET. After volume registration, the same three most representative axial slices from all sequences were combined into four-channel images to train the 2D-DenseNet264 network. Identical bounding boxes were selected on all scans and stacked into 4D volumes to train the 3D-DenseNet264 model. The test set consisted of 10-10-10 tumors. The performance of the models was compared using area under the receiver operating characteristic curve (AUROC), specificity, sensitivity, positive predictive values (PPV), negative predictive values (NPV), and f1 scores. RESULTS: The average AUC value of the 2D model (0.98) was slightly higher than that of the 3D model (0.94). Mean PPV, sensitivity, NPV, specificity and f1 scores (0.94, 0.93, 0.97, 0.97, and 0.93) of the 2D model were also superior to metrics of the 3D model (0.84, 0.83, 0.92, 0.92, and 0.83). The classification metrics of FNH were 0.91, 1.00, 1.00, 0.95, and 0.95 using the 2D and 0.90, 0.90, 0.95, 0.95, and 0.90 using the 3D models. The 2D and 3D networks' performance in the diagnosis of HCC were 1.00, 0.80, 0.91, 1.00, and 0.89 and 0.88, 0.70, 0.86, 0.95, and 0.78, respectively; while the evaluation of MET lesions resulted in 0.91, 1.00, 1.00, 0.95, and 0.95 and 0.75, 0.90, 0.94, 0.85, and 0.82 using the 2D and 3D networks, respectively. CONCLUSION: Both 2D and 3D-DenseNets can differentiate FNH, HCC and MET with good accuracy when trained on hepatocyte-specific contrast-enhanced multi-sequence MRI volumes.

Interobserver agreement and diagnostic accuracy of shearwave elastography for the staging of hepatitis C virus-associated liver fibrosis.

PURPOSE: Our study aimed to evaluate the technical success rate, interobserver reproducibility, and accuracy of shearwave elastography (SWE) in the staging of hepatitis C virus (HCV)-associated liver fibrosis. METHODS: A total of 10 healthy controls and 49 patients with chronic liver disease were enrolled prospectively. Two examiners performed point shearwave elastography (pSWE) and two-dimensional shearwave elastography (2D-SWE) measurements with an RS85A ultrasound scanner using the S-Shearwave application (Samsung Medison, Hongcheon, Korea). The performance of S-Shearwave in the staging (METAVIR F0-F4) of liver fibrosis was compared with prior transient elastography (TE) with receiver operating characteristic (ROC) curve analysis. RESULTS: The interobserver reproducibility was excellent with pSWE (ICC = 0.92, 95% CI: 0.86-0.95, P < .001). A very good agreement was found between pSWE and TE measurements (ICC =0.85, 95% CI: 0.78-0.89, P < .001). The ROC analysis determined the optimal cut-off values of pSWE for the staging of chronic hepatitis C-associated fibrosis (F2, 1.46 m/s; F3, 1.63 m/s; F4, 1.95 m/s). Both observers achieved excellent diagnostic accuracy (AUROC: 94% vs 97%) in the detection of significant (≥F2) liver fibrosis. CONCLUSION: The interobserver agreement is excellent with S-Shearwave pSWE, and observers can diagnose significant liver fibrosis with a comparable accuracy to TE.

Teachers' mindsets in medical education: A pilot survey of clinical supervisors.

Purpose: Current medical education models maintain that competencies such as professionalism and communication can be taught; however, some argue that certain attributes that make up these competencies, such as empathy, are fixed. Teachers' implicit theories, or mindsets (beliefs about the fixed versus learnable nature of human attributes) have been shown to impact their teaching and assessment practices; but little work has explored mindsets in medical education. We examined clinical supervisors' mindsets of two cognitive attributes (intelligence and clinical reasoning) and two affective attributes (moral character and empathy).Methods: Clinical supervisors (n = 40) from three specialities completed a survey designed to measure mindsets using two existing instruments for intelligence and moral character and 18 new items for clinical reasoning and empathy. Participants completed the survey twice for test-retest reliability (n = 25).Results: New items had satisfactory psychometric properties. Clinical supervisors' mindsets were mixed. Only 8% of participants saw clinical reasoning as fixed while more saw empathy (45%), intelligence (53%), and moral character (53%) as fixed - running counter to current educational models that characterize these attributes as learnable.Conclusion: This study provides evidence supporting the use of these new tools to measure mindsets that may help to better understand the impact of mindsets on medical education.

Interrelationship between iodine nutritional status of lactating mothers and their absolutely breast-fed infants in coastal districts of Gangetic West Bengal in India.

Iodine nutritional status of 128 lactating mothers and their breast-fed infants (1-3 months) from iodine-replete villages during post-salt iodization period was evaluated. Mothers' urine, blood, and breast milk (BM) and infants' urine and blood were collected and analyzed for iodine and serum FT4 and TSH estimation. Mothers' and infants' age, parity, occupation, education, and household income were recorded. Median urinary iodine concentration (UIC) of infants was 250 µg/L, indicating their iodine intake was more than adequate. Mothers' median UIC was 185 µg/L, indicating adequate iodine nutrition; however, 13.28% had mild to severe deficiency. Median breast milk iodine concentration (BMIC) was 230 µg/L, which was more than their median UIC 185 µg/L. In iodine-deficient mothers, positive correlation was found between mothers' and infants' serum FT4 and TSH levels, and negative correlation was found between mothers' and infants' serum FT4 and TSH levels in excessive iodine nutrition group. CONCLUSION: Iodine intake of breast-fed infants was at the limit of above requirement, and they are possibly at the risk of excess iodine intake. In iodine deficient and excessive iodine intake mothers, their infants' serum FT4 and TSH are independent on their iodine nutritional status but dependent on thyroid hormone profile of their mothers but differently. What is Known: • A median urinary iodine of 100 µg/L is used to define adequate iodine intake of lactating mothers and children < 2 years. However, adequate iodine intake in terms of urinary iodine of infants of age 1-3 months is not known. What is New: • Iodine intake of absolutely breast-fed infants (1-3 months) was more than adequate, though their mother's intake was adequate as breast milk contains more iodine than urine. The infants of iodine deficient and excessive iodine intake mothers, infants' hormonal profile is independent of their iodine nutritional status but dependent on their mothers thyroid hormone profile.

Use of an Innovative Simple Method for Anaerobiosis in the Diagnosis and Management of Infections in Two Unusual Cases.

Technical limitations restrict routine anaerobe isolation from clinical materials in resource-limited laboratories. An innovative two steps combustion candle jar technique may be suitable for such setup. This system was tried with one case of chronic osteomyelitis developed on supracondyler compound fracture. Porphyromonas spp. was isolated and identified. Vancomycin was recommended based on in vitro sensitivity test, but the leg was amputed after receiving a resistant drug gentamycin. While in another child with hydrocephalous, V-P shunt associated infection by Peptostreptococcus anaerobius was successfully controlled by sensitive drug vancomycin. These two eye-opener cases insisted us for large scale application of the technique.

Phenotypic Detection and Antibiogram of ß-lactamase-producing Proteus Species in a Tertiary Care Hospital, India.

BACKGROUND: Proteus species cause a variety of community- and hospital-acquired illnesses. Synthesis of ß-lactamases is the predominant mechanism for resistance to ß-lactam antibiotics. Among the ß-lactamases, extended spectrum ß-lactamases (ESBLs) and AmpC ß-lactamases are the most common. AIM: The objective of this study was to determine the occurrence of ESBL and AmpC ß-lactamases in Proteus species among various clinical isolates at a tertiary care hospital, India. MATERIALS AND METHODS: This study was done to identify various species of Proteus from clinical samples (n = 3922). Antimicrobial susceptibility was performed by Kirby-Bauer disc diffusion method. ESBL production was detected by modified double-disc synergy test and indirect modified three-dimensional tests and AmpC ß-lactamase production by AmpC disc test and modified Hodge test. RESULTS: Proteus species were isolated in 5.4% (101/1876) specimens. Three Proteus species isolated were Proteus mirabilis 62.4% (63/101), Proteus vulgaris 29.7% (30/101), and Proteus penneri 7.9% (8/101). ESBL producers confirmed by both tests were of 88.1% (89/101). Only AmpC ß-lactamase was produced by four isolates. Coproduction of ESBL and AmpC ß-lactamase was observed in 58.4% (52/89) of isolates. Twelve isolates were non-ß-lactamase producers. Multidrug resistance (MDR) was found in 95.1% (96/101) of isolates, 50.5% (51/101) were possibly extensively drug resistant and none were pan drug resistant. None of the isolates were resistant to piperacillin-tazobactam. P. penneri isolates exhibited high resistance to most of the antibiotics. CONCLUSIONS: A high prevalence of ESBL and AmpC ß-lactamases was found that concurrently showed MDR. Phenotypic methods for the detection of ß-lactamases are easy and simple and can be implemented in routine diagnostic laboratories along with susceptibility testing. These data will assist the clinicians in the management and control of infections.

Randomized clinical trial of fluid and salt restriction compared with a controlled liberal regimen in elective gastrointestinal surgery.

BACKGROUND: Excessive intravenous fluid prescription may play a causal role in postoperative complications following major gastrointestinal resectional surgery. The aim of this study was to investigate whether fluid and salt restriction would decrease postoperative complications compared with a more modern controlled liberal regimen. METHODS: In this observer-blinded single-site randomized clinical trial consecutive patients undergoing major gastrointestinal resectional surgery were randomized to receive either a liberal control fluid regimen or a restricted fluid and salt regimen. The primary outcome was postoperative complications of grade II and above (moderate to severe). RESULTS: Some 240 patients (194 colorectal resections and 46 oesophagogastric resections) were enrolled in the study; 121 patients were randomized to the restricted regimen and 119 to the control (liberal) regimen. During surgery the control group received a median (interquartile range) fluid volume of 2033 (1576-2500) ml and sodium input of 282 (213-339) mmol, compared with 1000 (690-1500) ml and 142 (93-218) mmol respectively in the restricted group. There was no significant difference in major complication rate between groups (38·0 and 39·0 per cent respectively). Median (range) hospital stay was 8 (3-101) days in the controls and 8 (range 3-76) days among those who received restricted fluids. There were four in-hospital deaths in the control group and two in the restricted group. Substantial differences in weight change, serum sodium, osmolality and urine : serum osmolality ratio were observed between the groups. CONCLUSION: There were no significant differences in major complication rates, length of stay and in-hospital deaths when fluid restriction was used compared with a more liberal regimen. REGISTRATION NUMBER: ISRCTN39295230 (http://www.controlled-trials.com).

Tumour necrosis factor-alpha and nitric oxide response in different categories of tuberculosis patients.

OBJECTIVE: To compare the magnitude of tumour necrosis factor alpha (TNF-α) and nitric oxide (NO) response in different categories of active tuberculosis (TB) patients by ex vivo experiment. DESIGN: New, relapsed (recurrent), miliary and pleural effusion TB cases were recruited with matched healthy controls. TNF-α and NO were measured from the culture supernatant of peripheral blood monocytes derived from cases and controls with and without challenge with live Mycobacterium tuberculosis H37Rv. RESULTS: TNF-α and NO production varied significantly among the different categories of TB patients. The magnitude was highest among patients with pleural effusion and lowest in miliary TB cases. In between, progressive decreases in response were noted in new and relapse cases. Overall, positive correlations between TNF-α and NO were noted among the diseased and healthy groups. CONCLUSION: Distinct TNF-α and NO levels appear to be associated with different clinical forms of TB and might help to assess prognosis and contribute to a better understanding of underlying immunopathological mechanisms.

Complications and reintervention following elective open abdominal aortic aneurysm repair: a 10-year retrospective analysis.

INTRODUCTION: Recent data have shown higher rates of graft related complication or reintervention in patients undergoing endovascular aneurysm repair compared with open aneurysm surgery (OAS). However, there are fewer data available regarding procedure related reinterventions following OAS. The aim of this study was to investigate the incidence of procedure related complications and reintervention following elective open abdominal aortic aneurysm repair. METHODS: This was a retrospective analysis of prospectively collected data from the dedicated Portsmouth POSSUM database. Data from 361 patients (median age: 72 years, 91.4% male) who underwent elective OAS between 1993 and 2004 were analysed. The incidences of early and late complications and subsequent reintervention were investigated. RESULTS: The median follow-up duration was 10 years 4 months (range: 5 years - 16 years 4 months). There were 52 reinterventions in the follow-up period. Of these, 34.6% were for incisional hernias or small bowel obstruction with the majority of the remaining laparotomies performed for bleeding or distal ischaemic complications. Almost two-thirds (63.5%) of reinterventions occurred in the first 30 days. There were 30 emergency readmissions to the acute surgical wards that did not require reintervention. CONCLUSIONS: OAS carries a significant reintervention rate. In this study, 54% of reinterventions were directly related to laparotomy.

Clinicopathological study of gall bladder carcinoma with special reference to gallstones: our 8-year experience from eastern India.

Gallbladder carcinoma (GBC) is the commonest cancer of the biliary tree and the most frequent cause of death from biliary malignancies. The incidence of GBC shows prominent geographic, age, race, and gender-related differences and is 4-7 times higher in patients with gallstones. This prompted us to study the clinicopathological aspects of the disease and the incidence of gallstones in gallbladder carcinoma patients, in this part of India. In this, combined retrospective (Jan 2004-March 2010) and prospective study (April 2010-Dec 2011) of eight years, 198 patients of gallbladder carcinoma (50 males and 148 females), (range 28-82 years; mean 55 years) were studied. Most of the patients were poor and presented with abdominal pain and mass, with abnormal lab parameters. Gallstones were present in 86% of patients. Surgical exploration was performed in 130, with gallbladder resection in 60 (including 7 incidental GBC). Adenocarcinoma (87.7%) was the commonest histological type. The study indicates that GBC is common in our scenario. It is a disease of elderly females, has a strong association with gallstones and every cholecystectomy specimen should be examined histopathologically.

A live-attenuated chimeric porcine circovirus type 2 (PCV2) vaccine is transmitted to contact pigs but is not upregulated by concurrent infection with porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) and is efficacious in a PCV2b-PRRSV-PPV challenge model.

The live chimeric porcine circovirus type 2 (PCV2) vaccine with the capsid gene of the emerging subtype 2b cloned in the genomic backbone of the nonpathogenic PCV1 is attenuated in vivo and induces protective immunity against PCV2. To further determine the safety and efficacy of this experimental vaccine, we tested for evidence of pig-to-pig transmission by commingling nonvaccinated and vaccinated pigs, determined potential upregulation by simultaneous vaccination and infection with porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV), and determined vaccine efficacy by challenging pigs 4 weeks after vaccination with PCV2b, PRRSV, and PPV. Forty-six 21-day-old, PCV2-naïve pigs were randomly assigned to one of six groups. Twenty-nine of 46 pigs were challenged with PCV2b, PRRSV, and PPV at day 28, 8/46 remained nonvaccinated and nonchallenged and served as negative controls, and 9/46 remained nonchallenged and served as vaccination controls. All animals were necropsied at day 49. PCV1-PCV2 viremia was detected in nonvaccinated contact pigs commingled with vaccinated pigs, indicating pig-to-pig transmission; however, PCV1-PCV2 DNA levels remained low in all vaccinated and contact pigs regardless of concurrent infection. Finally, vaccination 28 days before challenge resulted in significantly (P < 0.05) decreased amounts of PCV2 in tissues and sera and significantly (P < 0.05) reduced macroscopic and microscopic lesions. The results of this study indicate that the experimental live-attenuated chimeric PCV2 vaccine, although transmissible to contact pigs, remains attenuated in pigs concurrently infected with PRRSV and PPV and induces protective immunity against PCV2b when it is administered 28 days before PCV2 exposure.