Instrument-based Tests for Measuring Anterior Chamber Cells in Uveitis: A Systematic Review

ABSTRACT

Purpose

New instrument-based techniques for anterior chamber (AC) cell counting can offer automation and objectivity above clinician assessment. This review aims to identify such instruments and its correlation with clinician estimates.     

Bilateral Implantation of Centromedian‐Parafascicularis Complex and GPi: A New Combination of Unconventional Targets for Deep Brain Stimulation in Severe Parkinson Disease

Objectives. Traditional deep brain stimulation (DBS) at the subthalamic nucleus (STN) has proved to be efficacious on core Parkinsonian symptoms. However, very disabling l ‐dopa–induced abnormal involuntary movements (AIMs) and axial signs are slightly affected, suggesting that we target less conventional targets. Our candidates for DBS were the globus pallidus internus (GPi) plus the intralaminar thalamic complex (Pf or CM), given its extensive functional links with basal ganglia nuclei. Materials and Methods. The routine utilization of our innovative stereotactic apparatus allows us to implant, at the same time, both the CM‐Pf complex together with the GPi in six Parkinson disease patients. Both intraoperative and postoperative neurophysiologic assessments helped us recognize functional subregions while optimizing implantation of electrodes. Unified Parkinson disease rating scale (UPDRS) motor scores, AIMs, and freezing were carefully blindly evaluated for each condition. Results. A significant amelioration of UPDRS scores was achieved by simultaneous activation of both targets. CM‐Pf activation was only slightly effective in reducing rigidity and akinesia, but more efficacious on freezing. Not surprisingly, AIMs were peculiarly decreased by the activation of the permanent electro‐catheter in the posteroventral GPi. Conclusions. These findings confirm that, in selected patients, it is conceivable to target structures other than the conventional STN in order to maximize clinical benefit.     

A double cryptic chromosome imbalance is an important factor to explain phenotypic variability in Wolf-Hirschhorn syndrome

A total of five Wolf-Hirschhorn syndrome (WHS) patient with a 4p16.3 de novo microdeletion was referred because of genotype-phenotype inconsistencies, first explained as phenotypic variability of the WHS. The actual deletion size was found to be about 12 Mb in three patients, 5 Mb in another one and 20 Mb in the last one, leading us to hypothesize the presence of an extrachromosome segment on the deleted 4p. A der(4)(4qter --> p16.1::8p23 --> pter) chromosome, resulting from an unbalanced de novo translocation was, in fact, detected in four patients and a der(4)(4qter --> q32::4p15.3 --> qter) in the last. Unbalanced t(4;8) translocations were maternal in origin, the rec(4p;4q) was paternal. With the purpose of verifying frequency and specificity of this phenomenon, we investigated yet another group of 20 WHS patients with de novo large deletions (n = 13) or microdeletions (n = 7) and with apparently straightforward genotype-phenotype correlations. The rearrangement was paternal in origin, and occurred as a single anomaly in 19 out of 20 patients. In the remaining patient, the deleted chromosome 4 was maternally derived and consisted of a der(4)(4qter --> 4p16.3::8p23 --> 8pter). In conclusions, we observed that 20% (5/25) of de novo WHS-associated rearrangements were maternal in origin and 80% (20/25) were paternal. All the maternally derived rearrangements were de novo unbalanced t(4;8) translocations and showed specific clinical phenotypes. Paternally derived rearrangements were usually isolated deletions. It can be inferred that a double, cryptic chromosome imbalance is an important factor for phenotypic variability in WHS. It acts either by masking the actual deletion size or by doubling a quantitative change of the genome.     

Complex mosaic structural variations in human fetal brains

Somatic mosaicism, manifesting as single nucleotide variants (SNVs), mobile element insertions, and structural changes in the DNA, is a common phenomenon in human brain cells, with potential functional consequences. Using a clonal approach, we previously detected 200–400 mosaic SNVs per cell in three human fetal brains (15–21 wk postconception). However, structural variation in the human fetal brain has not yet been investigated. Here, we discover and validate four mosaic structural variants (SVs) in the same brains and resolve their precise breakpoints. The SVs were of kilobase scale and complex, consisting of deletion(s) and rearranged genomic fragments, which sometimes originated from different chromosomes. Sequences at the breakpoints of these rearrangements had microhomologies, suggesting their origin from replication errors. One SV was found in two clones, and we timed its origin to ∼14 wk postconception. No large scale mosaic copy number variants (CNVs) were detectable in normal fetal human brains, suggesting that previously reported megabase-scale CNVs in neurons arise at later stages of development. By reanalysis of public single nuclei data from adult brain neurons, we detected an extrachromosomal circular DNA event. Our study reveals the existence of mosaic SVs in the developing human brain, likely arising from cell proliferation during mid-neurogenesis. Although relatively rare compared to SNVs and present in ∼10% of neurons, SVs in developing human brain affect a comparable number of bases in the genome (∼6200 vs. ∼4000 bp), implying that they may have similar functional consequences.

Somatic mosaicism, the presence of more than one genotype in the somatic cells of an individual, is a prominent phenomenon in the human central nervous system. Forms of mosaicism include aneuploidies and smaller copy number variants (CNVs), structural variants (SVs), mobile element insertions, indels, and single nucleotide variants (SNVs). The developing human brain exhibits high levels of aneuploidy compared to other tissues, generating genetic diversity in neurons (Pack et al. 2005; Yurov et al. 2007; Bushman and Chun 2013). Such aneuploidy was suggested to be a natural feature of neurons, rather than a distinctive feature of neurodegeneration. However, the frequency of aneuploidy in neurons has been debated, with a separate study suggesting that aneuploidies occur in only about 2.2% of mature adult neurons (Knouse et al. 2014). They hence infer that such aneuploidy could have adverse effects at the cellular and organismal levels. Additionally, analysis of single cells from normal and pathological human brains identified large, private, and likely clonal somatic CNVs in both normal and diseased brains (Gole et al. 2013; McConnell et al. 2013; Cai et al. 2014; Knouse et al. 2016; Chronister et al. 2019; Perez-Rodriguez et al. 2019), with 3%–25% of human cerebral cortical nuclei carrying megabase-scale CNVs (Chronister et al. 2019) and deletions being twice as common as duplications (McConnell et al. 2013). Given that CNVs often arise from nonhomologous recombination and replication errors, their likely time of origin is during brain development. However, when CNVs first arise in human brain development has not yet been investigated. The present work is the first to examine this question using clonal populations of neuronal progenitor cells (NPCs) obtained from fetal human brains.Detection of CNVs in single neurons is challenging, given the need to amplify DNA. Such amplification may introduce artifacts that could, in turn, be misinterpreted as CNVs. In order to address this technical limitation, Hazen et al. reprogrammed adult postmitotic neurons using somatic cell nuclear transfer (SCNT) of neuronal nuclei into enucleated oocytes (Hazen et al. 2016). These oocytes then made sufficient copies of the neuronal genome allowing for whole-genome sequencing (WGS), thus eliminating the need for amplification in vitro. Using this method, they identified a total of nine structural variants in six neurons from mice, three of which were complex rearrangements. However, it is not possible to extend such studies to humans, given the ethical issues involved, besides the technical challenges in obtaining and cloning adult neurons. To circumvent the need of single-cell DNA amplification or nuclear cloning, we examined clonal cell populations obtained from neural progenitor cells from the frontal region of the cerebral cortex (FR), parietal cortex (PA) and basal ganglia (BG) and describe here the discovery and analysis of mosaic SVs in these NPCs (Bae et al. 2018). These clones were sequenced at 30× coverage (much higher than most previous single-cell studies), allowing identification of SVs other than large deletions and duplications as well as precise breakpoint resolution.     

Fatal fat embolism following amphotericin B lipid complex injection

A case of amphotericin B lipid complex induced fatal fat embolism is described. A 41-year-old Caucasian man with AIDS was undergoing treatment for cryptococcal meningitis with amphotericin B. His course was complicated by renal failure necessitating a change in therapy to amphotericin B lipid complex (Abelcet). At approximately 48 h, the patient developed tachycardia, tachypnea, respiratory failure, decline in hematocrit, thrombocytopenia, and alteration in mental status. Autopsy findings included fat emboli involving heart, lungs, kidney, and brain. To our knowledge, this is the first case report of a fatal fat embolism caused by intravenous liposome drug delivery.     

Bronchogenic squamous cell carcinoma metastasizing to Bowman''s capsule

A kidney metastasis from a squamous bronchogenic carcinoma is described that showed the unusual feature of occupying Bowman's capsule as well as metastasizing interstitially, producing a neoplastic ;crescent' formation. The lesion is compared with the histological picture of subacute glomerulonephritis. No explanation is offered for this route for metastasis.     

Antibiotic resistance in exopolysaccharide-forming Staphylococcus epidermidis clinical isolates from orthopaedic implant infections

The opportunistic pathogen Staphylococcus epidermidis is able to produce biofilm and to frequently cause implant infections. In recent years, it has also exhibited an increasing antimicrobial drug resistance. Here, the resistance to a panel of 16 different antibiotics in 342 clinical strains of S. epidermidis from orthopaedic implant infections has been investigated. The isolates were pheno- and genotyped for extracellular polysaccharide production, relevant to staphylococcal biofilm formation, in order to ascertain possible associations with antibiotic resistance. Approximately 10% of the isolates were found to be sensitive to all screened antibiotics. In all, 37-38% were resistant to beta-lactams such as oxacillin and imipenem, while the resistance to penicillin, ampicillin, cefazolin, cefamandole, was consistently observed in over 80% of the strains. Erythromycin- and clindamycin- resistant strains were approximately 41% and 16%, respectively. Of the isolates, 10% was resistant to chloramphenicol, 23% to sulfamethoxazole and 26% to ciprofloxacin. Resistance to vancomycin was never observed. Interestingly, exopolysaccharide-producing strains exhibited a significantly higher prevalence in the resistance to the four aminoglycosides (gentamicin, amikacin, netilmicin, tobramycin), to sulfamethoxazole and to ciprofloxacin with respect to non-producing isolates. Moreover, multiple resistance to antibiotics was more frequent among exopolysaccharide-forming strains.     

Expert opinion on the management and follow-up of uveitis patients during SARS-CoV-2 outbreak

ABSTRACT

Introduction

Routine medical and ophthalmic care is being drastically curtailed in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Uveitis patients require particular attention because of their theoretical risk of viral infection, in the context of therapeutic immunosuppression.     

Light scattering from aqueous solutions of poly(acrylamide-co-maleic anhydride)

Light scattering measurements from aqueous solutions for two samples of poly(acrylamide-co-maleic anhydride) in the presence of salt are conducted. One of the samples exhibits a negative initial slope and a minimum in the plot of the conventional reciprocal scattered intensity function of sin² (θ/2). The explanation for this anomaly is a large optical anisotropy of the segment. A correction for this effect of segmental anisotropy is made. The behaviour of the other sample of this copolymer is typical for a polyelectrolyte. By analysing the disymmetry of the scattered light, the influence of the salt concentration on the polyion is evidenced by the determination of the macromolecular dimensions. Light scattering data allow the evaluation of the Mark-Kuhn-Houwink exponent a for various degrees of dissociation of the polyion; a correlation between the variation of a and the shape of the macromolecule is observed.