Automatic Classification of Slit-Lamp Photographs by Imaging Illumination

PURPOSE

The aim of this study was to facilitate deep learning systems in image annotations for diagnosing keratitis type by developing an automated algorithm to classify slit-lamp photographs (SLPs) based on illumination technique.

METHODS

SLPs were collected from patients with corneal ulcer at Kellogg Eye Center, Bascom Palmer Eye Institute, and Aravind Eye Care Systems. Illumination techniques were slit beam, diffuse white light, diffuse blue light with fluorescein, and sclerotic scatter (ScS). Images were manually labeled for illumination and randomly split into training, validation, and testing data sets (70%:15%:15%). Classification algorithms including MobileNetV2, ResNet50, LeNet, AlexNet, multilayer perceptron, and k-nearest neighborhood were trained to distinguish 4 type of illumination techniques. The algorithm performances on the test data set were evaluated with 95% confidence intervals (CIs) for accuracy, F1 score, and area under the receiver operator characteristics curve (AUC-ROC), overall and by class (one-vs-rest).

RESULTS

A total of 12,132 images from 409 patients were analyzed, including 41.8% (n = 5069) slit-beam photographs, 21.2% (2571) diffuse white light, 19.5% (2364) diffuse blue light, and 17.5% (2128) ScS. MobileNetV2 achieved the highest overall F1 score of 97.95% (CI, 97.94%-97.97%), AUC-ROC of 99.83% (99.72%-99.9%), and accuracy of 98.98% (98.97%-98.98%). The F1 scores for slit beam, diffuse white light, diffuse blue light, and ScS were 97.82% (97.80%-97.84%), 96.62% (96.58%-96.66%), 99.88% (99.87%-99.89%), and 97.59% (97.55%-97.62%), respectively. Slit beam and ScS were the 2 most frequently misclassified illumination.

CONCLUSIONS

MobileNetV2 accurately labeled illumination of SLPs using a large data set of corneal images. Effective, automatic classification of SLPs is key to integrating deep learning systems for clinical decision support into practice workflows.

Use of ROC curve analysis for prediction gives fallacious results: Use predictivity-based indices

ABSTRACT

The area under the ROC curve is frequently used for assessing the predictive efficacy of a model, and the Youden index is commonly used to provide the optimal cut-off. Both are misleading tools for predictions. A ROC curve is drawn for the sensitivity of a quantitative test against its (1 - specificity) at different values of the test. Both sensitivity and specificity are retrospective in nature as these are indicators of correct classification of already known conditions. They are not indicators of future events and are not valid for predictions. Predictivity intimately depends on the prevalence which may be ignored by sensitivity and specificity. We explain this fallacy in detail and illustrate with several examples that the actual predictivity could differ greatly from the ROC curve-based predictivity reported by many authors. The predictive efficacy of a test or a model is best assessed by the percentage correctly predicted in a prospective framework. We propose predictivity-based ROC curves as tools for providing predictivities at varying prevalence in different populations. For optimal cut-off for prediction, in place of the Youden index, we propose a P-index where the sum of positive and negative predictivities is maximum after subtracting 1. To conclude, for correctly assessing adequacy of a prediction models, predictivity-based ROC curves should be used instead of the usual sensitivity-specificity-based ROC curves and the P-index should replace the Youden index.

Corneal Specialists' Confidence in Identifying Causal Organisms of Microbial Keratitis

PURPOSE

Microbial keratitis (MK) is a potentially blinding corneal disease caused by an array of microbial etiologies. However, the lack of early organism identification is a barrier to optimal care. We investigated clinician confidence in their diagnosis of organism type on initial presentation and the relationship between confidence and presenting features.

METHODS

This research presents secondary data analysis of 72 patients from the Automated Quantitative Ulcer Analysis (AQUA) study. Cornea specialists reported their confidence in organism identification. Presenting sample characteristics were recorded including patient demographics, health history, infection morphology, symptoms, and circumstances of infection. The association between confidence and presenting characteristics was investigated with 2-sample t-tests, Wilcoxon tests, and Chi-square or Fisher's exact tests.

RESULTS

Clinicians reported being "confident or very confident" in their diagnosis of the causal organism in MK infections for 39 patients (54%) and "not confident" for 33 patients (46%). Confidence was not significantly associated with patient demographics, morphologic features, or symptoms related to MK. MK cases where clinicians reported they were confident, versus not confident in their diagnosis, showed significantly smaller percentages of previous corneal disease (0% versus 15%, p = 0.017), were not seen by an outside provider first (69% versus 94%, p = 0.015), or had no prior labs drawn (8% versus 33%, p = 0.046), and a significantly larger percentage of cases wore contact lenses (54% versus 28%, p = 0.029).

CONCLUSION

In almost half of MK cases, cornea specialists reported lack of confidence in identifying the infection type. Confidence was related to ocular history and circumstances of infection but not by observable signs and symptoms or patient demographics. Tools are needed to assist clinicians with early diagnosis of MK infection type to expedite care and healing.

Microbial Keratitis Isolates at a Midwestern Tertiary Eye Care Center

PURPOSE

The aim of the study was to describe the pathogen, antimicrobial susceptibility, and trends over time of microbial keratitis (MK) at a Midwestern tertiary eye center.

METHODS

Patients with MK were identified in the electronic health record from August 2012 to December 2021. Diagnostic laboratory tests with an MK diagnosis were identified and classified as laboratory positive or laboratory negative. Laboratory-positive infections were categorized as bacterial (gram-positive, gram-negative, or acid-fast bacilli), fungal, viral, Acanthamoeba , or polymicrobial. Antimicrobial susceptibilities were obtained. Trends over time were assessed using linear regression.

RESULTS

Of 3288 patients with MK identified, 1012 (30.8%) had laboratory tests performed. Laboratory-positive infections (n = 499, 49.3%) were bacterial in 73.5% (n = 367) of cases, fungal in 7.8% (n = 39), viral in 1.6% (n = 8), Acanthamoeba in 1.4% (n = 7), and polymicrobial in 15.6% (n = 78). Of bacterial infections, 70% (n = 257) were gram-positive, with coagulase-negative Staphylococcus (CoNS; 31%) and Staphylococcus aureus ( S. aureus ; 23%) as the most common pathogens. Bacteria were acid-fast bacilli in 1.9% (n = 7) of cases and gram-negative in 28.1% (n = 103), with Pseudomonas aeruginosa as the predominant pathogen (47.7%). S. aureus showed antibiotic resistance from 0% (vancomycin and gentamicin) to 50% (erythromycin); CoNS from 0% (vancomycin, gentamicin, and moxifloxacin) to 64% (erythromycin). The rate of laboratory-negative MK significantly increased over time (slope estimate = 2.1% per year, P = 0.034). Rates of bacterial, fungal, viral, Acanthamoeba , and polymicrobial infections were stable over time (all slope P > 0.05).

CONCLUSIONS

Bacterial keratitis accounted for most MK cases. Gram-positive bacteria were the most common isolates. CoNS and S. aureus were universally susceptible to vancomycin. Rates of MK infection types were stable over time.

The effect of social determinants of health on severity of microbial keratitis presentation at a tertiary eye care hospital in Southern India

Purpose

Understanding the association between social determinants of health (SDoHs) and microbial keratitis (MK) can inform underlying risk for patients and identify risk factors associated with worse disease, such as presenting visual acuity (VA) and time to initial presentation.

Methods

This was a cross-sectional study was conducted with patients presenting with MK to the cornea clinic at a tertiary care hospital in Madurai, India. Patient demographics, SDoH survey responses, geographic pollution, and clinical features at presentation were collected. Descriptive statistics, univariate analysis, multi-variable linear regression models, and Poisson regression models were utilized.

Results

There were 51 patients evaluated. The mean age was 51.2 years (SD = 13.3); 33.3% were female and 55% did not visit a vision center (VC) prior to presenting to the clinic. The median presenting logarithm of the minimum angle of resolution (logMAR) VA was 1.1 [Snellen 20/240, inter-quartile range (IQR) = 20/80 to 20/4000]. The median time to presentation was 7 days (IQR = 4.5 to 10). The average particulate matter 2.5 (PM2.5) concentration, a measure of air pollution, for the districts from which the patients traveled was 24.3 μg/m3 (SD = 1.6). Age- and sex-adjusted linear regression and Poisson regression results showed that higher levels of PM2.5 were associated with 0.28 worse presenting logMAR VA (Snellen 2.8 lines, P = 0.002). Patients who did not visit a VC had a 100% longer time to presentation compared to those who did (incidence rate ratio = 2.0, 95% confidence interval = 1.3-3.0, P = 0.001).

Conclusion

Patient SDoH and environmental exposures can impact MK presentation. Understanding SDoH is important for public health and policy implications to mitigate eye health disparities in India.

Development of Novel Small-Molecule Activators of Pyruvate Kinase Muscle Isozyme 2, PKM2, to Reduce Photoreceptor Apoptosis

Treatment options are lacking to prevent photoreceptor death and subsequent vision loss. Previously, we demonstrated that reprogramming metabolism via the pharmacologic activation of PKM2 is a novel photoreceptor neuroprotective strategy. However, the features of the tool compound used in those studies, ML-265, preclude its advancement as an intraocular, clinical candidate. This study sought to develop the next generation of small-molecule PKM2 activators, aimed specifically for delivery into the eye. Compounds were developed that replaced the thienopyrrolopyridazinone core of ML-265 and modified the aniline and methyl sulfoxide functional groups. Compound 2 demonstrated that structural changes to the ML-265 scaffold are tolerated from a potency and efficacy standpoint, allow for a similar binding mode to the target, and circumvent apoptosis in models of outer retinal stress. To overcome the low solubility and problematic functional groups of ML-265, compound 2's efficacious and versatile core structure for the incorporation of diverse functional groups was then utilized to develop novel PKM2 activators with improved solubility, lack of structural alerts, and retained potency. No other molecules are in the pharmaceutical pipeline for the metabolic reprogramming of photoreceptors. Thus, this study is the first to cultivate the next generation of novel, structurally diverse, small-molecule PKM2 activators for delivery into the eye.

Optimising plasma clozapine levels to improve treatment response: an individual patient data meta-analysis and receiver operating characteristic curve analysis

BACKGROUND

Although clozapine is the most efficacious medication for treatment-refractory schizophrenia, not all patients will have an adequate response. Optimising clozapine dose using therapeutic drug monitoring could therefore maximise response.

AIMS

Using individual patient data, we undertook a receiver operating characteristic (ROC) curve analysis to determine an optimal therapeutic range for clozapine levels to guide clinical practice.

METHOD

We conducted a systematic review of PubMed, PsycINFO and Embase for studies that provided individual participant level data on clozapine levels and response. These data were analysed using ROC curves to determine the prediction performance of plasma clozapine levels for treatment response.

RESULTS

We included data on 294 individual participants from nine studies. ROC analysis yielded an area under the curve of 0.612. The clozapine level at the point of optimal diagnostic benefit was 372 ng/mL; at this level, the response sensitivity was 57.3%, and specificity 65.7%. The interquartile range for treatment response was 223-558 ng/mL. There was no improvement in ROC performance with mixed models including patient gender, age or length of trial. Clozapine dose and clozapine concentration to dose ratio did not provide significantly meaningful prediction of response to clozapine.

CONCLUSIONS

Clozapine dose should be optimised based on clozapine therapeutic levels. We found that a range between 250 and 550 ng/mL could be recommended, while noting that a level of >350 ng/mL is the most optimal for response. Although some patients may not respond without clozapine levels >550 ng/mL, the benefits should be weighed against the increased risk of adverse drug reactions.

Synthetic high-density lipoprotein nanoparticles delivering rapamycin for the treatment of age-related macular degeneration

Synthetic high-density lipoprotein (sHDL) and rapamycin (Rap) have both been shown to be potential treatments for age-related macular degeneration (AMD). The low aqueous solubility of Rap, however, limits its therapeutic utility. Here we used an Apolipoprotein A-I mimetic peptide and phospholipid-based sHDL for the intravitreal delivery of Rap. By incorporation of Rap in sHDL nanoparticles (sHDL-Rap), we achieve 125-fold increase in drug aqueous concentration. When applied in vitro to retinal pigment epithelium cells, sHDL-Rap exhibited the abilities to efflux cholesterol, neutralize endotoxin, and suppress NF-κB activation. As an mTOR inhibitor, Rap induced autophagy and inhibited NF-κB-mediated pro-inflammatory signaling. Additionally, a greater reduction in lipofuscin accumulation and increased anti-inflammatory effects were achieved by sHDL-Rap relative to free drug or sHDL alone. In vivo studies demonstrated that sHDL reached the target retina pigment epithelium (RPE) layer following intravitreal administration in rats. These results suggest that sHDL-Rap holds potential as a treatment for AMD.

Safety Evaluation of Photoacoustic Tomography System for Intraocular Tumors

Purpose

Photoacoustic tomography (PAT) has demonstrated the ability to characterize molecular components and architectural heterogeneities of intraocular tumors in enucleated human globes and in animals in vivo. Although laser safety levels have been established for illumination through the cornea, the safety limit for PAT illumination through the sclera has not been investigated. The purpose of this study is to examine if the energy level used in intraocular PAT results in ocular damage.

Methods

Rabbit eyes were exposed to pulsed laser illumination at 20 mJ/cm² at the scleral surface. Eyes were examined at 1, 7, and 28 days after the laser exposure. Examination procedures included white light and fluorescence fundus imaging, optical coherence tomography (OCT), electroretinography (ERG), and histology with hematoxylin and eosin (H&E) staining as well as terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL staining).

Results

Fundus imaging and OCT of rabbit eyes at 1, 7, and 28 days following exposure of the laser illumination of the PAT system did not reveal any damage to the retinal structures. ERG showed no significant difference between the experimental and control eyes. Similarly, H&E histology did not show abnormalities in either the scleral tissue where the laser illumination was delivered or in the retinal layers. No sign of apoptosis in the layers of the retina, choroid, or optic nerve was found on TUNEL staining.

Conclusions

Similar to the application of PAT to other organs, the proposed laser illumination energy level at 20 mJ/cm² does not impose detectable harm to the ocular tissue.

Translational Relevance

This study addresses illumination safety issues for PAT.

Open-Source Automatic Biomarker Measurement on Slit-Lamp Photography to Estimate Visual Acuity in Microbial Keratitis

Purpose

To assess clinical applicability of automatic image analysis in microbial keratitis (MK) by evaluating the relationship between biomarker measurements on slit-lamp photography (SLP) and best-corrected visual acuity (BCVA).

Methods

Seventy-six patients with MK with SLP images and same-day logarithm of the minimum angle of resolution (logMAR) BCVA were evaluated. MK biomarkers (stromal infiltrate, white blood cell infiltration, corneal edema, hypopyon, epithelial defect) were segmented manually by ophthalmologists and automatically by a novel, open-source, deep learning–based segmentation algorithm. Five measurements (presence, maximum width, total area, proportion of the corneal limbus area affected, centrality) were calculated. Correlations between the measurements and BCVA were calculated. An automatic regression model estimated BCVA from the measurements. Differences in performance between using manual and automatic measurements were evaluated using William's test (for correlation) and the paired-sample t-test (for absolute error).

Results

Measurements had high correlations of 0.86 (manual) and 0.84 (automatic) with true BCVA. Estimated BCVA had average (mean ± SD) absolute errors of 0.39 ± 0.27 logMAR (manual, median: 0.30) and 0.35 ± 0.28 logMAR (automatic, median: 0.30) and high correlations of 0.76 (manual) and 0.80 (automatic) with true BCVA. Differences between using manual and automatic measurements were not statistically significant for correlations of measurements with true BCVA (P = .66), absolute errors of estimated BCVA (P = .15), or correlations of estimated BCVA with true BCVA (P = .60).

Conclusions

The proposed algorithm measured MK biomarkers as accurately as ophthalmologists. Measurements were highly correlated with and estimative of visual acuity.

Translational Relevance

This study demonstrates the potential of developing fully automatic objective and standardized strategies to aid ophthalmologists in the clinical assessment of MK.

Hexokinase 2 is dispensable for photoreceptor development but is required for survival during aging and outer retinal stress

Photoreceptor death is the ultimate cause of vision loss in many retinal degenerative conditions. Identifying novel therapeutic avenues for prolonging photoreceptor health and function has the potential to improve vision and quality of life for patients suffering from degenerative retinal disorders. Photoreceptors are metabolically unique among other neurons in that they process the majority of their glucose via aerobic glycolysis. One of the main regulators of aerobic glycolysis is hexokinase 2 (HK2). Beyond its enzymatic function of phosphorylating glucose to glucose-6-phosphate, HK2 has additional non-enzymatic roles, including the regulation of apoptotic signaling via AKT signaling. Determining the role of HK2 in photoreceptor homeostasis may identify novel signaling pathways that can be targeted with neuroprotective agents to boost photoreceptor survival during metabolic stress. Here we show that following experimental retinal detachment, p-AKT is upregulated and HK2 translocates to mitochondria. Inhibition of AKT phosphorylation in 661W photoreceptor-like cells results in translocation of mitochondrial HK2 to the cytoplasm, increased caspase activity, and decreased cell viability. Rod-photoreceptors lacking HK2 upregulate HK1 and appear to develop normally. Interestingly, we found that HK2-deficient photoreceptors are more susceptible to acute nutrient deprivation in the experimental retinal detachment model. Additionally, HK2 appears to be important for preserving photoreceptors during aging. We show that retinal glucose metabolism is largely unchanged after HK2 deletion, suggesting that the non-enzymatic role of HK2 is important for maintaining photoreceptor health. These results suggest that HK2 expression is critical for preserving photoreceptors during acute nutrient stress and aging. More specifically, p-AKT mediated translocation of HK2 to the mitochondrial surface may be critical for protecting photoreceptors from acute and chronic stress.

Small molecule activation of metabolic enzyme pyruvate kinase muscle isozyme 2, PKM2, circumvents photoreceptor apoptosis

Photoreceptor cell death is the ultimate cause of vision loss in many retinal disorders, and there is an unmet need for neuroprotective modalities to improve photoreceptor survival. Similar to cancer cells, photoreceptors maintain pyruvate kinase muscle isoform 2 (PKM2) expression, which is a critical regulator in aerobic glycolysis. Unlike PKM1, which has constitutively high catalytic activity, PKM2 is under complex regulation. Recently, we demonstrated that genetically reprogramming photoreceptor metabolism via PKM2-to-PKM1 substitution is a promising neuroprotective strategy. Here, we explored the neuroprotective effects of pharmacologically activating PKM2 via ML-265, a small molecule activator of PKM2, during acute outer retinal stress. We found that ML-265 increased PKM2 activity in 661 W cells and in vivo in rat eyes without affecting the expression of genes involved in glucose metabolism. ML-265 treatment did, however, alter metabolic intermediates of glucose metabolism and those necessary for biosynthesis in cultured cells. Long-term exposure to ML-265 did not result in decreased photoreceptor function or survival under baseline conditions. Notably, though, ML-265-treatment did reduce entrance into the apoptotic cascade in in vitro and in vivo models of outer retinal stress. These data suggest that reprogramming metabolism via activation of PKM2 is a novel, and promising, therapeutic strategy for photoreceptor neuroprotection.

Magnetic Hyperthermia in Y79 Retinoblastoma and ARPE-19 Retinal Epithelial Cells: Tumor Selective Apoptotic Activity of Iron Oxide Nanoparticle

Purpose

To evaluate selective apoptosis of Y79 retinoblastoma versus ARPE-19 retinal pigment epithelial cells by using different doses of dextran-coated iron oxide nanoparticles (DCIONs) in a magnetic hyperthermia paradigm.

Methods

Y79 and ARPE-19 cells were exposed to different concentrations of DCIONs, namely, 0.25, 0.5, 0.75, and 1 mg/ml. After 2 hours of incubation, cells were exposed to a magnetic field with a frequency of 250 kHz and an amplitude of 4 kA/m for 30 minutes to raise the cellular temperature between 42 and 46°C. Y79 and ARPE-19 cells incubated with DCION without magnetic field exposure were used as controls. Cell viability and apoptosis were assessed at 4, 24, and 72 hours after hyperthermia treatment.

Results

At 4 hours following magnetic hyperthermia, cell death for Y79 cells was 1%, 8%, 17%, and 17% for 0.25, 0.5, 0.75 and 1 mg/ml of DCION, respectively. Cell death increased to 47%, 59%, 70%, and 75% at 24 hours and 16%, 45%, 50%, and 56% at 72 hours for 0.25, 0.5, 0.75, and 1 mg/ml of DCIONs, respectively. Magnetic hyperthermia did not have any significant toxic effects on ARPE-19 cells at all DCION concentrations, and minimal baseline cytotoxicity of DCIONs on Y79 and ARPE-19 cells was observed without magnetic field activation. Gene expression profiling showed that genes involved in FAS and tumor necrosis factor alpha signaling pathways were activated in Y79 cells following hyperthermia. Caspase 3/7 activity in Y79 cells increased following treatment, consistent with the activation of caspase-mediated apoptosis and loss of cell viability by magnetic hyperthermia.

Conclusion

Magnetic hyperthermia using DCIONs selectively kills Y79 cells at 0.5 mg/ml or higher concentrations via the activation of apoptotic pathways.

Translational Relevance

Magnetic hyperthermia using DCIONs might play a role in targeted management of retinoblastoma.

Ocular Toxicity Profile of ST-162 and ST-168 as Novel Bifunctional MEK/PI3K Inhibitors

PURPOSE

ST-162 and ST-168 are small-molecule bifunctional inhibitors of MEK and PI3K signaling pathways that are being developed as novel antitumor agents. Previous small-molecule and biologic MEK inhibitors demonstrated ocular toxicity events that were dose limiting in clinical studies. We evaluated in vitro and in vivo ocular toxicity profiles of ST-162 and ST-168.

METHODS

Photoreceptor cell line 661W and adult retinal pigment epithelium cell line ARPE-19 were treated with increasing concentrations of bifunctional inhibitors. Western blots, cell viability, and caspase activity assays were performed to evaluate MEK and PI3K inhibition and dose-dependent in vitro toxicity, and compared with monotherapy. In vivo toxicity profile was assessed by intravitreal injection of ST-162 and ST-168 in Dutch-Belted rabbits, followed by ocular examination and histological analysis of enucleated eyes.

RESULTS

Retinal cell lines treated with ST-162 or ST-168 exhibited dose-dependent inhibition of MEK and PI3K signaling. Compared with inhibition by monotherapies and their combinations, bifunctional inhibitors demonstrated reduced cell death and caspase activity. In vivo, both bifunctional inhibitors exhibited a more favorable toxicity profile when compared with MEK inhibitor PD0325901.

CONCLUSIONS

Novel MEK and PI3K bifunctional inhibitors ST-162 and ST-168 demonstrate favorable in vitro and in vivo ocular toxicity profiles, supporting their further development as potential therapeutic agents targeting multiple aggressive tumors.

Photoreceptor metabolic reprogramming provides survival advantage in acute stress while causing chronic degeneration

Photoreceptor death is the root cause of vision loss in many retinal disorders, and there is an unmet need for neuroprotective modalities to improve photoreceptor survival. The biosynthetic requirement of photoreceptors is among the highest in the body, and to meet this demand, photoreceptors maintain their ability to perform aerobic glycolysis. This highly regulated form of glycolysis allows cells to efficiently budget their metabolic needs and may be a critical link between photoreceptor function and survival. Pyruvate kinase muscle isozyme 2 (PKM2) is a key regulator of aerobic glycolysis. In the present study, we characterized the effect of PKM2 deletion on baseline functioning and survival of photoreceptors over time by utilizing a photoreceptor-specific, PKM2 knockout mouse model. We found that upon PKM2 deletion, PKM1 is upregulated in the outer retina and there is increased expression of genes involved in glucose metabolism, which led to chronic degenerative changes in the outer retina of these mice. We also discovered that this metabolic reprogramming provided a survival advantage to photoreceptors in an experimental model of retinal detachment. This study strongly supports the hypothesis that reprogramming metabolism may be a novel therapeutic strategy for photoreceptor neuroprotection during acute stress.

FAS apoptotic inhibitory molecule 2 is a stress-induced intrinsic neuroprotective factor in the retina

We report the neuroprotective role of FAS apoptotic inhibitory molecule 2 (FAIM2), an inhibitor of the FAS signaling pathway, during stress-induced photoreceptor apoptosis. Retinal detachment resulted in increased FAIM2 levels in photoreceptors with higher amounts detected at the tips of outer segments. Activation of FAS death receptor via FAS-ligand led to JNK-mediated FAIM2 phosphorylation, decreased proteasome-mediated degradation and increased association with the FAS receptor. Photoreceptor apoptosis was accelerated in Faim2 knockout mice following experimental retinal detachment. We show that FAIM2 is primarily involved in reducing stress-induced photoreceptor cell death but this effect was transient. FAIM2 was found to interact with both p53 and HSP90 following the activation of the FAS death pathway and FAIM2/HSP90 interaction was dependent on the phosphorylation of FAIM2. Lack of FAIM2 led to increased expression of proadeath genes Fas and Ripk1 in the retina under physiologic conditions. These results demonstrate that FAIM2 is an intrinsic neuroprotective factor activated by stress in photoreceptors and delays FAS-mediated photoreceptor apoptosis. Modulation of this pathway to increase FAIM2 expression may be a potential therapeutic option to prevent photoreceptor death.

Impact of a multidimensional infection control strategy on central line-associated bloodstream infection rates in pediatric intensive care units of five developing countries: findings of the International Nosocomial Infection Control Consortium (INICC)

PURPOSE

To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional infection control strategy including a practice bundle to reduce the rates of central line-associated bloodstream infection (CLAB) in patients hospitalized in pediatric intensive care units (PICUs) of hospitals, which are members of the INICC, from nine cities of five developing countries: Colombia, India, Mexico, Philippines, and Turkey.

METHODS

CLAB rates were determined by means of a prospective surveillance study conducted on 1,986 patients hospitalized in nine PICUs, over a period of 12,774 bed-days. The study was divided into two phases. During Phase 1 (baseline period), active surveillance was performed without the implementation of the multi-faceted approach. CLAB rates obtained in Phase 1 were compared with CLAB rates obtained in Phase 2 (intervention period), after implementation of the INICC multidimensional infection control program.

RESULTS

During Phase 1, 1,029 central line (CL) days were recorded, and during Phase 2, after implementing the CL care bundle and interventions, we recorded 3,861 CL days. The CLAB rate was 10.7 per 1,000 CL days in Phase 1, and in Phase 2, the CLAB rate decreased to 5.2 per 1,000 CL days (relative risk [RR] 0.48, 95% confidence interval [CI] 0.29-0.94, P = 0.02), showing a reduction of 52% in the CLAB rate.

CONCLUSIONS

This study shows that the implementation of a multidimensional infection control strategy was associated with a significant reduction in the CLAB rates in the PICUs of developing countries.

Socioeconomic impact on device-associated infections in limited-resource neonatal intensive care units: findings of the INICC

PURPOSE

To evaluate the impact of country socioeconomic status and hospital type on device-associated healthcare-associated infections (DA-HAIs) in neonatal intensive care units (NICUs).

METHODS

Data were collected on DA-HAIs from September 2003 to February 2010 on 13,251 patients in 30 NICUs in 15 countries. DA-HAIs were defined using criteria formulated by the Centers for Disease Control and Prevention. Country socioeconomic status was defined using World Bank criteria.

RESULTS

Central-line-associated bloodstream infection (CLA-BSI) rates in NICU patients were significantly lower in private than academic hospitals (10.8 vs. 14.3 CLA-BSI per 1,000 catheter-days; p < 0.03), but not different in public and academic hospitals (14.6 vs. 14.3 CLA-BSI per 1,000 catheter-days; p = 0.86). NICU patient CLA-BSI rates were significantly higher in low-income countries than in lower-middle-income countries or upper-middle-income countries [37.0 vs. 11.9 (p < 0.02) vs. 17.6 (p < 0.05) CLA-BSIs per 1,000 catheter-days, respectively]. Ventilator-associated-pneumonia (VAP) rates in NICU patients were significantly higher in academic hospitals than in private or public hospitals [13.2 vs. 2.4 (p < 0.001) vs. 4.9 (p < 0.001) VAPs per 1,000 ventilator days, respectively]. Lower-middle-income countries had significantly higher VAP rates than low-income countries (11.8 vs. 3.8 per 1,000 ventilator-days; p < 0.001), but VAP rates were not different in low-income countries and upper-middle-income countries (3.8 vs. 6.7 per 1,000 ventilator-days; p = 0.57). When examined by hospital type, overall crude mortality for NICU patients without DA-HAIs was significantly higher in academic and public hospitals than in private hospitals (5.8 vs. 12.5%; p < 0.001). In contrast, NICU patient mortality among those with DA-HAIs was not different regardless of hospital type or country socioeconomic level.

CONCLUSIONS

Hospital type and country socioeconomic level influence DA-HAI rates and overall mortality in developing countries.

Device-associated nosocomial infection rates in intensive care units of seven Indian cities. Findings of the International Nosocomial Infection Control Consortium (INICC)

We sought to determine the rate of healthcare-associated infection (HCAI), microbiological profile, bacterial resistance, length of stay (LOS) and excess mortality in 12 ICUs of the seven hospital members of the International Infection Control Consortium (INICC) of seven Indian cities. Prospective surveillance was introduced from July 2004 to March 2007; 10 835 patients hospitalized for 52 518 days acquired 476 HCAIs, an overall rate of 4.4%, and 9.06 HCAIs per 1000 ICU-days. The central venous catheter-related bloodstream infection (CVC-BSI) rate was 7.92 per 1000 catheter-days;the ventilator-associated pneumonia (VAP) rate was 10.46 per 1000 ventilator-days; and the catheter-associated urinary tract infection (CAUTI) rate was 1.41 per 1000 catheter-days. Overall 87.5% of all Staphylococcus aureus HCAIs were caused by meticillin-resistant strains, 71.4% of Enterobacteriaceae were resistant to ceftriaxone and 26.1% to piperacillin-tazobactam; 28.6% of the Pseudomonas aeruginosa strains were resistant to ciprofloxacin, 64.9% to ceftazidime and 42.0% to imipenem. LOS of patients was 4.4 days for those without HCAI, 9.4 days for those with CVC-BSI, 15.3 days for those with VAP and 12.4 days for those with CAUTI. Excess mortality was 19.0% [relative risk (RR) 3.87; P < or = 0.001] for VAP, 4.0% (RR 1.60; P=0.0174) for CVC-BSI, and 11.6% (RR 2.74; P=0.0102) for CAUTI. Data may not accurately reflect the clinical setting of the country and variations regarding surveillance may have affected HCAI rates. HCAI rates, LOS, mortality and bacterial resistance were high. Infection control programmes including surveillance and antibiotic policies are a priority in India.

The 'Delhi active test' for detection of anterior cruciate ligament tears

All the described tests for the detection of anterior cruciate ligament (ACL) tear are passive tests. For obese or muscular built patients these tests are cumbersome and often unsuitable. We describe for the first time a new method, the 'Delhi active test', by which a torn ACL can be detected irrespective of the size or build of the patient. The results of this test are reproducible and the diagnostic accuracy is comparable with other tests. We suggest that the 'Delhi active test' be used as one of the routine clinical methods to detect the torn ACL.

Haemodynamic responses to laryngoscopy and intubation in patients with pregnancy-induced hypertension: effect of intravenous esmolol with or without lidocaine

The pressor response is known to be exaggerated in patients with pregnancy-induced hypertension, which can result in increased morbidity and mortality in both mother and newborn. Various pharmacological agents have been used before induction in an attempt to attenuate the adrenergic response but with varying degree of success. Esmolol, an ultra short-acting cardioselective beta-blocker with rapid onset and short elimination half-life, is an attractive choice for attenuating the adrenergic response in pregnant patients. In a prospective, randomised double blind study we evaluated the efficacy of two bolus doses of esmolol with or without lidocaine, in patients with pregnancy-induced hypertension. Eighty such patients undergoing lower segmental caesarean section were randomly divided into four groups and received the following study drugs before intubation: group I, esmolol 1 mg.kg(-1); group II, esmolol 2 mg.kg(-1); group III, esmolol 1 mg.kg(-1) and lidocaine 1.5 mg.kg(-1); and group IV, esmolol 2 mg.kg(-1) and lidocaine 1.5 mg.kg(-1). In groups II, III and IV, the changes in maternal heart rate, systolic blood pressure and mean arterial pressure in response to laryngoscopy and intubation were attenuated to a comparable degree (P > 0.05). No adverse effects were noticed in mother or baby. We conclude that esmolol 1 mg.kg(-1) with lidocaine 1.5 mg.kg(-1) is effective in attenuating the adrenergic responses to laryngoscopy and intubation in patients with pregnancy-induced hypertension.

The styloid process in ossicular chain reconstruction. II: Long-term analysis

The human cadaveric styloid process was used as a homograft material for ossicular chain reconstruction in 41 cases of chronic suppurative otitis media over a five-year period. Although technical success was achieved in about 88.23 per cent of the cases, actual patient benefit was around 70.58 per cent; this is comparable to results obtained with most other homologous graft materials. The problem of breakage while remodelling the bone has also increased the risk of transmitting the AIDS virus and consequently undermines the use of this material.