Increasing impact of COVID-19 on young adults: evidence from hospitalisations in Brazil.

OBJECTIVES: Concerns about the increasing impact of severe COVID-19 in younger individuals in Brazil came after a recent synchronised country-wide wave of cases in Brazil. This communication analyses how hospitalisations due to COVID-19 changed in the age groups 18-49 years and ≥70 years. STUDY DESIGN: Longitudinal study based on secondary data. METHODS: Data from SIVEP-Gripe, a public and open-access database of Severe Acute Respiratory Illness records (including COVID-19 notifications), were used in this study. Statistical control charts examined changes in the magnitude and variation of younger (18-49 years) and older (≥70 years) adults who were hospitalised between 15th March 2020 and 19th June 2021. RESULTS: During the few first weeks of the pandemic in Brazil, the number of COVID-19 hospitalisations increased in older adults but decreased in younger adults. Subsequently, hospitalisations reached statistical control zones in epidemiological weeks (EW) 19-48 of 2020 (EW 19-48/2020) and EW 03-05/2021 (18-49 y, mean = 26.1%; ≥70 y, mean = 32.8%). Between EW 49/2020 and EW 02/2021, the number of hospitalisations of younger adults dropped to levels below the lower control limit. In contrast, the number of hospitalisations of older adults surpassed the upper limit of the corresponding statistical control zones. However, from EW 06/2021, numbers of hospitalisations changed from statistical control zones, with hospitalisations of younger adults increasing and reaching 44.9% in EW 24/2021 and hospitalisations of older adults decreasing until EW 19/2021 (14.1%) and reaching 17.3% in EW 24/2021. CONCLUSIONS: An increasing number of COVID-19 hospitalisations were observed in younger adults from EW 06/2021. This could be a result of the successful vaccination programme in older adults, who were initially prioritised, and possibly an increased exposure to highly transmissible variants of COVID-19 in younger adults who had to go to work in the absence of social protection (i.e. government financial support). Potential consequences of COVID-19 hospitalisations in younger adults could include a reduced life expectancy of the population and an increased number of people unable to perform daily activities due to post-COVID-19 conditions.

Decision trees for optimizing the minimum detectable concentration of radioxenon detectors.

We present a novel application of machine learning techniques to optimize the design of a radiation detection system. A decision tree-based algorithm is described which greedily optimizes partitioning of energy depositions based on a minimum detectable concentration metric - appropriate for radiation measurement. We apply this method to the task of optimizing sensitivity to radioxenon decays in the presence of a high rate of radon-progeny backgrounds (i.e., assuming no physical radon removal by traditional gas separation techniques). Assuming other backgrounds are negligible, and considering sensitivity to each xenon isotope separately (neglecting interference between isotopes), we find that, in general, high resolution readout and high spatial segmentation yield little additional capability to discriminate against radon backgrounds compared to simpler detector designs.

Mapping infected cell phenotype.

Quantitative modeling of the phenotypic changes in the host cell during the bacterial infection makes it possible to explore an empirical relation between the infection stages and the quantifiable host-cell phenotype. A statistically reliable model of this relation can facilitate therapeutic defense against threats due to natural and genetically engineered bacterium. In the preliminary experiment, we have collected several thousand cell images over a period of 72 h of infection with a 2-h sampling frequency that covers various stages of infection by Francisella tularenesis (Ft). Segmentation of macrophages in images was accomplished using a fully automatic, parallel region growing technique. Over two thousand feature descriptors for the host cell were calculated. Multidimensional scaling, followed by hierarchical clustering, was used to group the cells. Preliminary results show that the host-cell phenotype, as defined by the set of measureable features, groups into different classes that can be mapped to the stages of infection.

Scalp abscess due to Salmonella typhimurium-- a case report.

The incidence of non-typhoidal salmonellosis has markedly increased in the past decade. Localised infection develops in approximately 5-10% of persons with salmonella bacteraemia. In this report, a 4-year-old female child suffering from acute lymphoid leukaemia is presented with high grade intermittent fever. Pustular lesions were observed over the right side of the scalp. The scalp abscess was drained and pus was sent for culture and sensitivity. Culture grew Salmonella typhimurium. Blood culture also grew the same organism. She had an uneventful recovery after treatment.

The influence of sampling duration on recovery of culturable fungi using the Andersen N6 and RCS bioaerosol samplers.

UNLABELLED: The influence of sampling duration on recovery of culturable fungi was compared using the Andersen N6 and the Reuter Centrifugal Sampler (RCS). Samplers were operated side-by-side, collecting 15 samples each of incrementally increasing duration (1-15 min). From 270 samples collected, 26 fungal genera were recovered. Species of Alternaria, Aspergillus, Cladosporium, Epicoccum, Penicillium and Ulocladium were most frequent. Data adjusted to CFU/m3 were fitted to a Poisson regression model with a logarithmic link function and evaluated for the impact of sampling time on qualitative and quantitative recovery of fungi, both as individual taxa and in aggregate according to xerotolerance. Significant differences between the two samplers were observed for xerotolerant and normotolerant moulds, as well as Aspergillus spp. and Cladosporium spp. With the exception of Cladosporium spp., overall recoveries were higher with the RCS. When the Andersen N6 was used, the recovered levels of Cladosporium spp. and unidentified yeasts were reduced significantly at sampling times over 6 min. Similarly, when the RCS was used, recovery of Aspergillus spp., Penicillium spp., Ulocladium spp., unidentified yeasts, and low water activity fungi declined significantly at sampling times over 6 min. PRACTICAL IMPLICATIONS: Currently, the industry-wide trend for viable air sampling in indoor environmental investigations is to use sampling times between 2 and 4 min in duration. Our results support the routine use of a 6-min sampling time where low spore loads are expected, resulting in improved limits of detection.

Recurrent respiratory papillomatosis complicated by aspergillosis: a case report with review of literature.

Pulmonary extension of recurrent invasive papillomatosis often poses a diagnostic challenge to the examining bronchoscopist, pathologist, radiologist and surgeon, in distinguishing it as a benign lesion that is confined to the mucosa and extending along the branches of the tracheobronchial tree from true invasion of a malignant tumor. We document here a case of recurrent invasive respiratory papillomatosis which initially presented as a laryngeal papilloma. After multiple recurrences, the patient presented with bronchopulmonary involvement, complicated by invasive aspergillosis in a non-immunocompromised setting.

An outbreak of extended spectrum beta-lactamase producing Klebsiella pneumoniae in a neonatal intensive care unit.

Klebsiella pneumoniae has long been a prominent cause of nosocomial infections and outbreaks have been observed in the intensive care units and in high risk groups. We present here a brief report on an outbreak of Klebsiella pneumoniae which occurred in a neonatal intensive care unit in our teaching hospital. As neonates are at highest risk for acquisition of Klebsiella pneumoniae producing extended spectrum beta-lactamase, infection control policies and procedures should be strictly followed to prevent such outbreaks.

Pseudoaneurysm of the popliteal artery. Surgical management of 3 cases.

Pseudoaneurysm of the popliteal artery is much less common than true aneurysm in this location. We report 3 cases of popliteal artery pseudoaneurysms, each of differing etiopathology, one presenting 3 months after trauma, one following aortic valve replacement for aortic regurgitation with suspected endocarditis, with no organism detected, and the 3rd of infective etiology. The clinical presentation and surgical management are discussed with a review of the literature.

Pbhyd1 and Pbhyd2: two mycelium-specific hydrophobin genes from the dimorphic fungus Paracoccidioides brasiliensis.

Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus which is found as mycelia (M) at 26 degrees C and as yeasts (Y) at 37 degrees C, or after the invasion of host tissues. Although the dimorphic transition in P. brasiliensis and other dimorphic fungi is an essential step in the establishment of infection, the molecular events regulating this process are yet poorly understood. Since the differential gene expression is a well-known mechanism which plays a central role in the dimorphic transition as well as in other biological process, in this work we describe the identification and characterization of two differentially expressed P. brasiliensis hydrophobin cDNAs (Pbhyd1 and Pbhyd2). Hydrophobins are small hydrophobic proteins related to a variety of important functions in fungal biology, including cell growth, development, infection, and virulence. These two hydrophobin genes are present as single copy in P. brasiliensis genome and Northern blot analysis revealed that both mRNAs are mycelium-specific and highly accumulated during the first 24 h of M to Y transition.

Transcriptome characterization of the dimorphic and pathogenic fungus Paracoccidioides brasiliensis by EST analysis.

Paracoccidioides brasiliensis is a pathogenic fungus that undergoes a temperature-dependent cell morphology change from mycelium (22 degrees C) to yeast (36 degrees C). It is assumed that this morphological transition correlates with the infection of the human host. Our goal was to identify genes expressed in the mycelium (M) and yeast (Y) forms by EST sequencing in order to generate a partial map of the fungus transcriptome. Individual EST sequences were clustered by the CAP3 program and annotated using Blastx similarity analysis and InterPro Scan. Three different databases, GenBank nr, COG (clusters of orthologous groups) and GO (gene ontology) were used for annotation. A total of 3,938 (Y = 1,654 and M = 2,274) ESTs were sequenced and clustered into 597 contigs and 1,563 singlets, making up a total of 2,160 genes, which possibly represent one-quarter of the complete gene repertoire in P. brasiliensis. From this total, 1,040 were successfully annotated and 894 could be classified in 18 functional COG categories as follows: cellular metabolism (44%); information storage and processing (25%); cellular processes-cell division, posttranslational modifications, among others (19%); and genes of unknown functions (12%). Computer analysis enabled us to identify some genes potentially involved in the dimorphic transition and drug resistance. Furthermore, computer subtraction analysis revealed several genes possibly expressed in stage-specific forms of P. brasiliensis. Further analysis of these genes may provide new insights into the pathology and differentiation of P. brasiliensis.

Recent advances in the MOBJ algorithm for training artificial neural networks.

This paper presents a new scheme for training MLPs which employs a relaxation method for multi-objective optimization. The algorithm works by obtaining a reduced set of solutions, from which the one with the best generalization is selected. This approach allows balancing between the training error and norm of network weight vectors, which are the two objective functions of the multi-objective optimization problem. The method is applied to classification and regression problems and compared with Weight Decay (WD), Support Vector Machines (SVMs) and standard Backpropagation (BP). It is shown that the systematic procedure for training proposed results on good generalization neural models, and outperforms traditional methods.

Surgical experience with congenital heart disease in Down's syndrome.

Children with Down's syndrome and congenital heart defects have multiple problems. The role of cardiac surgery in the management of these patients was investigated by reviewing the clinical data, hospital course and follow-up of 21 patients (9 males and 12 females, age range 1 month to 14 years) with Down's syndrome and congenital heart defects operated in our institute. Twelve (57%) of these were infants and nine (43%), older children. Five were in congestive cardiac failure, four were hypothyroid. The heart lesions ranked in incidence as follows: atrioventricular septal defect 7 (33.3%), tetralogy of Fallot 3 (14.3%), tetralogy of Fallot & atrioventricular septal defect both 2 (9.5%), double outlet right ventricle with pulmonary stenosis 1 (4.8%), patent ductus arteriosus 2 (9.5%), patent ductus arteriosus plus coarctation 1 (4.8%), ventricular septal defect 2 (9.5%), atrial septal defect plus ventricular septal defect 1 (4.8%), atrial septal defect plus patent ductus arteriosus plus right pulmonary artery stenosis 1 (4.8%) and transposition of great arteries with multiple ventricular septal defect 1 (4.8%). Four (19%) patients had palliative procedures while the rest (81%) underwent primary repair. All survived the operation. The post-operative period was complicated in 6 (28.5%), with respiratory infections in 3, pulmonary hypertensive crisis in 2 and complete heart block in 1. The early mortality was 0, while there were 2 (9.5%) late deaths. The number of hospitalisations was markedly reduced according to the parents. Follow-up showed near normal pulmonary artery pressure in 50 percent children with large shunts and a good developmental spurt was seen in 60 percent. From a purely surgical viewpoint, the prognosis for children with Down's syndrome and congenital heart disease is good.

Cardiac tumors.

Primary cardiac tumours of the heart are rare. Primary cardiac neoplasms are benign in 75% cases. Among the benign lesions about 40% are myxomas. Approximately 25% of primary cardiac neoplasms are malignant and almost all are sarcomas and lymphomas of varying types. Clinical evaluation has been augmented by echocardiography, angiography, radionuclide studies, computed tomography and magnetic resonance imaging. Benign tumours are amenable to resection and in selected patients with malignant cardiac disease surgical intervention may be feasible.

RNA and protein catalysis in group II intron splicing and mobility reactions using purified components.

Group II introns encode proteins with reverse transcriptase activity. These proteins also promote RNA splicing (maturase activity) and then, with the excised intron, form a site-specific DNA endonuclease that promotes intron mobility by reverse splicing into DNA followed by target DNA-primed reverse transcription. Here, we used an Escherichia coli expression system for the Lactococcus lactis group II intron Ll.LtrB to show that the intron-encoded protein (LtrA) alone is sufficient for maturase activity, and that RNP particles containing only the LtrA protein and excised intron RNA have site-specific DNA endonuclease and target DNA-primed reverse transcriptase activity. Detailed analysis of the splicing reaction indicates that LtrA is an intron-specific splicing factor that binds to unspliced precursor RNA with a K(d) of

A bacterial group II intron encoding reverse transcriptase, maturase, and DNA endonuclease activities: biochemical demonstration of maturase activity and insertion of new genetic information within the intron.

The Lactococcus lactis group II intron Ll.ltrB is similar to mobile yeast mtDNA group II introns, which encode reverse transcriptase, RNA maturase, and DNA endonuclease activities for site-specific DNA insertion. Here, we show that the Lactococcal intron can be expressed and spliced efficiently in Escherichia coli. The intron-encoded protein LtrA has reverse transcriptase and RNA maturase activities, with the latter activity shown both in vivo and in vitro, a first for any group II intron-encoded protein. As for the yeast mtDNA introns, the DNA endonuclease activity of the Lactococcal intron is associated with RNP particles containing both the intron-encoded protein and the excised intron RNA. Also, the intron RNA cleaves the sense-strand of the recipient DNA by a reverse splicing reaction, whereas the intron-encoded protein cleaves the antisense strand. The Lactococcal intron endonuclease can be obtained in large quantities by coexpression of the LtrA protein with the intron RNA in E. coli or reconstituted in vitro by incubating the expressed LtrA protein with in vitro-synthesized intron RNA. Furthermore, the specificity of the endonuclease and reverse splicing reactions can be changed predictably by modifying the RNA component. Expression in E. coli facilitates the use of group II introns for the targeting of specific foreign sequences to a desired site in DNA.

Analysis of the CYT-18 protein binding site at the junction of stacked helices in a group I intron RNA by quantitative binding assays and in vitro selection.

The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) functions in splicing group I introns by promoting the formation of the catalytically active structure of the intron RNA. Previous studies showed that CYT-18 binds with high affinity to the P4-P6 domain of the catalytic core and that there is some additional contribution to binding from the P3-P9 domain. Here, quantitative binding assays with deletion derivatives of the N. crassa mitochondrial large rRNA intron showed that at least 70% of the binding energy can be accounted for by the interaction of CYT-18 with the P4-P6 domain. Within this domain, P4 and P6 are required for high affinity CYT-18 binding, while the distal elements P5 and P6a may contribute indirectly by stabilizing the correct structure of the binding site in P4 and P6. CYT-18 binds to a small RNA corresponding to the isolated P4-P6 domain, but not to a permuted version of this RNA in which P4-P6 is a continuous rather than a stacked helix. Iterative in vitro selection experiments with the isolated P4-P6 domain showed a requirement for base-pairing to maintain helices P4, P6 and P6a, but indicate that P5 is subject to fewer constraints. The most strongly conserved nucleotides in the selections were clustered around the junction of the P4-P6 stacked helix, with ten nucleotides (J3/4-2,3, P4 bp -1 and 3, and P6 bp -1 and 2) found invariant in the context of the wild-type RNA structure. In vitro mutagenesis confirmed that replacement of the wild-type nucleotides at J3/4-2 and 3 or P4 bp-3 markedly decreased CYT-18 binding, reflecting either base specific contacts or indirect readout of RNA structure by the protein. Our results suggest that a major function of CYT-18 is to promote assembly of the P4-P6 domain by stabilizing the correct geometry at the junction of the P4-P6 stacked helix. The relatively large number of conserved nucleotides at the binding site suggests that the interaction of CYT-18 with group I introns is unlikely to have arisen by chance and could reflect either an evolutionary relationship between group I introns and tRNAs or interaction with a common stacked-helical structural motif that evolved separately in these RNAs.

Surgical management of left ventricular myxoma with embolization to the right coronary artery.

We report a rare case of left ventricular myxoma with embolization to the right coronary artery, presenting as an acute myocardial infarction. The tumor was excised from the left ventricle, and the tumor embolus was removed from the right coronary artery. Saphenous vein bypass grafting was also performed successfully.