A 63-year-old woman with common variable immunodeficiency (CVID) presented with 1 year of insidious onset lower extremity pain and weakness. She underwent a circuitous workup, failed to improve despite treatment for various presumed diagnoses. She presented to a University physical medicine and rehabilitation clinic with continued symptoms. Electrophysiologic testing was recommended revealing a lower extremity motor greater than sensory axonal neuropathy. While CVID has known central nervous system complications, to our knowledge, this represents the second known reported case of peripheral neuropathy. We review the literature on CVID and summarize neurological disease mechanisms and manifestations. Although peripheral neuropathy is a rarely documented complication of CVID, providers need to be aware of potential peripheral nervous system complications of primary immune deficiencies such as CVID due to its significant impact on physical performance, balance, and fall risks.

Prcis

Tracking failure frequency (TFF) increases with dry eye symptom severity and in the left eye.

Purpose

Symptoms of dry eye disease are commonly encountered in glaucoma patients and can be exacerbated by topical glaucoma medications. Dry eye disease may influence the reliability of visual field (VF) tests and impact the accurate interpretation of the results.

Patients and methods

Patients at the Veterans Administration Medical Center San Diego completed the 5-item Dry Eye Questionnaire before VF testing between December 2018 and February 2019. VF reliability metrics were recorded for each patient. Standard reliability metrics included fixation losses, false positive, and false negative rates. Gaze tracking (GT) metrics included percent of stimuli with gaze deviations between 1 and 2 degrees, 3 and 5 degrees, 6 degrees or greater, and percent of stimuli with tracking failure (TFF). The use of glaucoma medications and artificial tears was also recorded.

Results

A total of 494 patients completed the 5-item Dry Eye Questionnaire and VF testing. There was no association between dry eye symptom severity and standard reliability metrics or most GT metrics. However, TFF increased as dry eye symptom severity increased (P=0.015). TFF was also greater in the left eye, which was tested second (P=0.012); no other reliability metrics were related to laterality. Patients were more likely to use artificial tears with increased dry eye symptom severity (P<0.001), but there was no relationship between symptom severity and glaucoma medication use.

Discussion

Dry eye symptom severity may influence the acceptable range or threshold of TFF when using GT metrics to determine VF reliability. Likewise, the acceptable range or threshold for TFF may be different between eyes.

Unraveling the mechanisms of microbial adaptive evolution following genetic or environmental challenges is of fundamental interest in biological science and engineering. When the challenge is the loss of a metabolic enzyme, adaptive responses can also shed significant insight into metabolic robustness, regulation, and areas of kinetic limitation. In this study, whole-genome sequencing and high-resolution ¹³C-metabolic flux analysis were performed on 10 adaptively evolved pgi knockouts of Escherichia coliPgi catalyzes the first reaction in glycolysis, and its loss results in major physiological and carbon catabolism pathway changes, including an 80% reduction in growth rate. Following adaptive laboratory evolution (ALE), the knockouts increase their growth rate by up to 3.6-fold. Through combined genomic-fluxomic analysis, we characterized the mutations and resulting metabolic fluxes that enabled this fitness recovery. Large increases in pyridine cofactor transhydrogenase flux, correcting imbalanced production of NADPH and NADH, were enabled by direct mutations to the transhydrogenase genes sthA and pntAB The phosphotransferase system component crr was also found to be frequently mutated, which corresponded to elevated flux from pyruvate to phosphoenolpyruvate. The overall energy metabolism was found to be strikingly robust, and what have been previously described as latently activated Entner-Doudoroff and glyoxylate shunt pathways are shown here to represent no real increases in absolute flux relative to the wild type. These results indicate that the dominant mechanism of adaptation was to relieve the rate-limiting steps in cofactor metabolism and substrate uptake and to modulate global transcriptional regulation from stress response to catabolism.

Purpose

To compare standard reliability metrics and gaze tracking (GT) metrics on the Humphrey field analyzer (HFA).

Design

Retrospective cross-sectional study.

Methods

The study was performed at the VA Medical Center, San Diego, and included 494 glaucoma and glaucoma suspect patients who had an HFA 24-2 SITA Fast visual field (VF) performed in both eyes. Standard reliability metrics (fixation loss [FL], false-positive [FP], and false-negative [FN]) were compared to GT metrics (deviations of 1°-2° [M1], deviations of 3°-5° [M3], deviations >6° [M6], and tracking failure frequency [TFF]). The main outcome measures were Spearman rank-based correlation coefficient and area under the receiver operating characteristic (AUROC) curves between standard and GT reliability metrics.

Results

The 95th percentile limits for GT metrics were 66.7% for M1, 67.5% for M3, 49.5% for M6, and 79.8% for TFF. There were statistically significant correlations between standard and GT reliability metrics using the 95th percentile as a binary cutoff for GT metrics. However, low Spearman correlation values and AUROC calculations suggest little clinical significance of the associations. FN increased as VF severity worsened (P < .001). M6 was lower in eyes with mild compared to moderate and advanced VF loss (P = .012).

Conclusions

GT metrics do not have a clinically significant association with standard reliability metrics. Both FN and M6 are influenced by VF severity. Aggregate GT metrics do not aid in reliability assessment. These findings suggest that GT metrics may provide an alternative or complementary measure of VF reliability.

Adaptive laboratory evolution (ALE) is a widely-used method for improving the fitness of microorganisms in selected environmental conditions. It has been applied previously to Escherichia coli K-12 MG1655 during aerobic exponential growth on glucose minimal media, a frequently used model organism and growth condition, to probe the limits of E. coli growth rate and gain insights into fast growth phenotypes. Previous studies have described up to 1.6-fold increases in growth rate following ALE, and have identified key causal genetic mutations and changes in transcriptional patterns. Here, we report for the first time intracellular metabolic fluxes for six such adaptively evolved strains, as determined by high-resolution ¹³C-metabolic flux analysis. Interestingly, we found that intracellular metabolic pathway usage changed very little following adaptive evolution. Instead, at the level of central carbon metabolism the faster growth was facilitated by proportional increases in glucose uptake and all intracellular rates. Of the six evolved strains studied here, only one strain showed a small degree of flux rewiring, and this was also the strain with unique genetic mutations. A comparison of fluxes with two other wild-type (unevolved) E. coli strains, BW25113 and BL21, showed that inter-strain differences are greater than differences between the parental and evolved strains. Principal component analysis highlighted that nearly all flux differences (95%) between the nine strains were captured by only two principal components. The distance between measured and flux balance analysis predicted fluxes was also investigated. It suggested a relatively wide range of similar stoichiometric optima, which opens new questions about the path-dependency of adaptive evolution.

Purpose

Despite increasing electronic health record (EHR) adoption, perceptions of EHRs are negative among ophthalmologists due to concerns about productivity, costs, and documentation. The authors evaluated the effects of EHR adoption in an oculoplastics practice, which had not been previously studied.

Methods

Clinical volume, documentation time, time spent with patients, reimbursement, relative value units, and patient satisfaction were examined for 2 academic oculoplastics attendings between April 2018 and April 2019, with EHR implementation in September 2018.

Results

The mean number of patients seen in a half-day clinic was 31.8 versus 27.7 (p = 0.018) pre- and post-EHR implementation, respectively. EHR implementation had no effect on total monthly reimbursement (p = 0.88) or total monthly relative value units (p = 0.54). Average reimbursement (p = 0.004) and relative value units (p = 0.001) per patient encounter were significantly greater with EHR use. Patient satisfaction scores improved (p = 0.018). Mean physician time per patient increased from 6.4 to 9.0 minutes (p < 0.001). Mean documentation time per patient increased from 1.7 to 3.6 minutes (p < 0.001). Average patient wait times decreased by 9 minutes (p = 0.03) with EHR use. No scribes were used.

Conclusions

EHR implementation was associated with decreased patient volume without significant differences in total reimbursement. Although EHR adoption was associated with increased physician time devoted to patients and greater time expenditure on documentation, patients experienced decreased wait times. This suggests that EHR use streamlined the overall clinic flow without sacrificing physicians' time with the patient. The author's findings suggest that EHR implementation can be accomplished in an academic oculoplastics setting without negative impact on patient experience or reimbursement considerations.

13C-Metabolic flux analysis (13C-MFA) traditionally assumes that kinetic isotope effects from isotopically labeled compounds do not appreciably alter cellular growth or metabolism, despite indications that some biochemical reactions can be non-negligibly impacted. Here, populations of Escherichia coli were adaptively evolved for ~1000 generations on uniformly labeled 13C-glucose, a commonly used isotope for 13C-MFA. Phenotypic characterization of these evolved strains revealed ~40% increases in growth rate, with no significant difference in fitness when grown on either labeled (13C) or unlabeled (12C) glucose. The evolved strains displayed decreased biomass yields, increased glucose and oxygen uptake, and increased acetate production, mimicking what is observed after adaptive evolution on unlabeled glucose. Furthermore, full genome re-sequencing revealed that the key genetic changes underlying these phenotypic alterations were essentially the same as those acquired during adaptive evolution on unlabeled glucose. Additionally, glucose competition experiments demonstrated that the wild-type exhibits no isotopic preference for unlabeled glucose, and the evolved strains have no preference for labeled glucose. Overall, the results of this study indicate that there are no significant differences between 12C and 13C-glucose as a carbon source for E. coli growth.

Genotype-fitness maps of evolution have been well characterized for biological components, such as RNA and proteins, but remain less clear for systems-level properties, such as those of metabolic and transcriptional regulatory networks. Here, we take multi-omics measurements of 6 different E. coli strains throughout adaptive laboratory evolution (ALE) to maximal growth fitness. The results show the following: (i) convergence in most overall phenotypic measures across all strains, with the notable exception of divergence in NADPH production mechanisms; (ii) conserved transcriptomic adaptations, describing increased expression of growth promoting genes but decreased expression of stress response and structural components; (iii) four groups of regulatory trade-offs underlying the adjustment of transcriptome composition; and (iv) correlates that link causal mutations to systems-level adaptations, including mutation-pathway flux correlates and mutation-transcriptome composition correlates. We thus show that fitness landscapes for ALE can be described with two layers of causation: one based on system-level properties (continuous variables) and the other based on mutations (discrete variables). IMPORTANCE Understanding the mechanisms of microbial adaptation will help combat the evolution of drug-resistant microbes and enable predictive genome design. Although experimental evolution allows us to identify the causal mutations underlying microbial adaptation, it remains unclear how causal mutations enable increased fitness and is often explained in terms of individual components (i.e., enzyme rate) as opposed to biological systems (i.e., pathways). Here, we find that causal mutations in E. coli are linked to systems-level changes in NADPH balance and expression of stress response genes. These systems-level adaptation patterns are conserved across diverse E. coli strains and thus identify cofactor balance and proteome reallocation as dominant constraints governing microbial adaptation.

Background

Cardiovascular disease is the leading cause of mortality and disability worldwide. A noninvasive test that can detect underlying cardiovascular disease has the potential to identify patients at risk prior to the occurrence of adverse cardiovascular events. We sought to determine whether an easily observed imaging finding indicative of retinal ischemia, which we term 'retinal ischemic perivascular lesions' (RIPLs), could serve as a biomarker for cardiovascular disease.

Methods

We reviewed optical coherence tomography (OCT) scans of individuals, with no underlying retinal pathology, obtained at UC San Diego Health from July 2014 to July 2019. We identified 84 patients with documented cardiovascular disease and 76 healthy controls. OCT scans were assessed for evidence of RIPLs. In addition, the 10-year atherosclerotic cardiovascular disease (ASCVD) risk calculator was used to risk-stratify the subjects into four different categories.

Findings

Patients with documented cardiovascular disease had higher number of RIPLs compared to healthy controls (2.8 vs 0.8, p < 0.001). After adjusting for age, sex, smoking history, systolic blood pressure and triglycerides, cholesterol and hemoglobin A1C levels, each RIPL was associated with an odds ratio of having cardiovascular disease of 1·60 (1.09-2>37). The number of RIPLs in individuals with intermediate and high 10-year ASCVD risk scores was higher than in those with low ASCVD risk scores (1.7 vs 0.64, p = 0.02 and 2.9 vs 0.64, p 0.002, respectively).

Interpretation

The presence of RIPLs, which are anatomical markers of prior retinal ischemic infarcts, is suggestive of coexisting cardiovascular disease. RIPLs detection, obtained from routine retinal scans, may thus provide an additional biomarker to identify patients at risk of developing adverse cardiovascular events.

Funding

None.

Purpose

The purpose of this study was to evaluate the ability to align two types of retinal images taken on different platforms; color fundus (CF) photographs and infrared scanning laser ophthalmoscope (IR SLO) images using mathematical warping and artificial intelligence (AI).

Methods

We collected 109 matched pairs of CF and IR SLO images. An AI algorithm utilizing two separate networks was developed. A style transfer network (STN) was used to segment vessel structures. A registration network was used to align the segmented images to each. Neither network used a ground truth dataset. A conventional image warping algorithm was used as a control. Software displayed image pairs as a 5 × 5 checkerboard grid composed of alternating subimages. This technique permitted vessel alignment determination by human observers and 5 masked graders evaluated alignment by the AI and conventional warping in 25 fields for each image.

Results

Our new AI method was superior to conventional warping at generating vessel alignment as judged by masked human graders (P < 0.0001). The average number of good/excellent matches increased from 90.5% to 94.4% with AI method.

Conclusions

AI permitted a more accurate overlay of CF and IR SLO images than conventional mathematical warping. This is a first step toward developing an AI that could allow overlay of all types of fundus images by utilizing vascular landmarks.

Translational relevance

The ability to align and overlay imaging data from multiple instruments and manufacturers will permit better analysis of this complex data helping understand disease and predict treatment.