A 12-year follow up survey of childhood blindness at schools for the blind in Cambodia

BACKGROUND

Cambodia is a low-income country in South East Asia with a population of 15.5 million people of whom 4.9 million (38%) are under the age of 16. The causes of childhood blindness in Cambodia have not been investigated since the first survey of schools for the blind done in 2009 by our group. Given the large demographic and economic shifts in Cambodia since 2009 it is important to determine if these causes have changed in order to ensure intervention programmes are appropriately targeted. The purpose of the present study is to investigate the prevalence of causes of childhood blindness at schools for the blind in Cambodia.

METHODS

Students between the ages of 5 and 16 years who were attending schools for the blind in Cambodia were examined by a consultant paediatric ophthalmologist and had clinical photographs taken. Distance visual acuity was measured using a logMAR tumbling E chart and the WHO definitions of blindness and severe visual impairment were used. The examining ophthalmologist recorded the anatomical site and aetiology of vision loss using the WHO Prevention of Blindness eye examination record for children. Collected data were compared to a previous survey from 2009.

RESULTS

Data from 73 students were included for analysis. The most common anatomical location of abnormality causing vision loss was the cornea (n = 20, 33.9%) followed by the lens and retina (n = 11, 18.64% each). Hereditary factors (n = 29, 49.15%) and childhood diseases (n = 27, 45.76%) were the most common aetiological causes of childhood blindness. The majority (71.19%) of childhood blindness was avoidable. The present study did not demonstrate 0a significant difference in the causes of childhood blindness compared to 2009.

CONCLUSIONS

Corneal pathologies continue to represent the most common cause of vision loss amongst the surveyed population and the majority of causes of childhood blindness continue to be avoidable. These findings will facilitate the development of evidence-based targeted interventional programmes in Cambodia.

Cryptococcal endophthalmitis complicated by immune reconstitution inflammatory syndrome in a renal transplant recipient: A case report and review of the literature

A 59 year old male renal transplant recipient developed endogenous cryptococcal endophthalmitis which was complicated by immune reconstitution inflammatory syndrome (IRIS). Herein we report a novel diagnostic test using lateral flow assay, the management of cryptococcal endophthalmitis and the novel complication of intraocular IRIS in a solid organ transplant recipient.

Salvageable waste associated with intravitreal injections: A local medical waste management approach

BACKGROUND

Healthcare waste management is a globally challenging issue with an increased prevalence of disposable, single-use materials in developed countries and a rapidly ageing population continuing to drive an increase in the use of medical resources. One manifestation of this within ophthalmology is the increasing number of intravitreal injections given for conditions such as age-related macular degeneration and diabetic macular oedema.

METHODS

A prospective controlled cohort study was performed over 5 weeks in 2021 during which two sites were selected to compare different approaches to sorting the waste generated by intravitreal injections. At Site A all waste associated with these injections was placed in standard hospital waste bins. Site B was the intervention arm where a real-time sorting of waste occurred. The number of injections given and waste amounts were recorded.

RESULTS

116 and 286 injections were given at Sites A and B, respectively over the study period. Site A generated an average of 470.7 g of waste per injection compared with 175.1 g at our intervention site. This represents a 62.8% reduction (p < 0.001). At Site B, where waste was sorted, a total of 50.1 kg of medical waste was generated from these injections during the study period of which 33.8 kg (67.5%) was salvageable.

CONCLUSIONS

This is the first quantification of the medical waste associated with intravitreal injections, a burgeoning treatment for macular degeneration and diabetic retinopathy among other conditions. This study demonstrates a significant reduction in the amount of medical waste produced using an easily implementable real-world methodology.

Does selective evaluation of gastric aspirates in preterm infants influence time to full enteral feeding?

The use of routine gastric aspiration in the assessment of feeding intolerance is widespread in neonatal practice. Our article seeks to answer the clinical question, 'In premature infants receiving feeds via nasogastric or orogastric tube [P], does routine evaluation of gastric aspirates [I] compared with selective evaluation of gastric aspirates [C] reduce the time taken to establish full feeds without complications [O]?' Articles were identified through MEDLINE and reference lists from the sources found were reviewed for additional publications. Three papers were critically appraised and National Health and Medical Research Centre grades of level of evidence have been assigned to each. We found limited evidence to either support or reject the practice of routine gastric aspiration in preterm infants. There were no increases in the rates of significant complications in studies underpowered for this outcome. The decision to perform routine or selective gastric aspiration should be determined by individual centres. A large scale randomised controlled trial would be of significant benefit in determining the value of routine gastric aspiration in preterm infants.

Molecular and Cellular Mechanisms for Trapping and Activating Emotional Memories

Recent findings suggest that memory allocation to specific neurons (i.e., neuronal allocation) in the amygdala is not random, but rather the transcription factor cAMP-response element binding protein (CREB) modulates this process, perhaps by regulating the transcription of channels that control neuronal excitability. Here, optogenetic studies in the mouse lateral amygdala (LA) were used to demonstrate that CREB and neuronal excitability regulate which neurons encode an emotional memory. To test the role of CREB in memory allocation, we overexpressed CREB in the lateral amygdala to recruit the encoding of an auditory-fear conditioning (AFC) memory to a subset of neurons. Then, post-training activation of these neurons with Channelrhodopsin-2 was sufficient to trigger recall of the memory for AFC, suggesting that CREB regulates memory allocation. To test the role of neuronal excitability in memory allocation, we used a step function opsin (SFO) to transiently increase neuronal excitability in a subset of LA neurons during AFC. Post-training activation of these neurons with Volvox Channelrhodopsin-1 was able to trigger recall of that memory. Importantly, our studies show that activation of the SFO did not affect AFC by either increasing anxiety or by strengthening the unconditioned stimulus. Our findings strongly support the hypothesis that CREB regulates memory allocation by modulating neuronal excitability.

Large-Scale Fluorescence Calcium-Imaging Methods for Studies of Long-Term Memory in Behaving Mammals

During long-term memory formation, cellular and molecular processes reshape how individual neurons respond to specific patterns of synaptic input. It remains poorly understood how such changes impact information processing across networks of mammalian neurons. To observe how networks encode, store, and retrieve information, neuroscientists must track the dynamics of large ensembles of individual cells in behaving animals, over timescales commensurate with long-term memory. Fluorescence Ca(2+)-imaging techniques can monitor hundreds of neurons in behaving mice, opening exciting avenues for studies of learning and memory at the network level. Genetically encoded Ca(2+) indicators allow neurons to be targeted by genetic type or connectivity. Chronic animal preparations permit repeated imaging of neural Ca(2+) dynamics over multiple weeks. Together, these capabilities should enable unprecedented analyses of how ensemble neural codes evolve throughout memory processing and provide new insights into how memories are organized in the brain.

Synaptic tagging during memory allocation

There is now compelling evidence that the allocation of memory to specific neurons (neuronal allocation) and synapses (synaptic allocation) in a neurocircuit is not random and that instead specific mechanisms, such as increases in neuronal excitability and synaptic tagging and capture, determine the exact sites where memories are stored. We propose an integrated view of these processes, such that neuronal allocation, synaptic tagging and capture, spine clustering and metaplasticity reflect related aspects of memory allocation mechanisms. Importantly, the properties of these mechanisms suggest a set of rules that profoundly affect how memories are stored and recalled.

Molecular and cellular approaches to memory allocation in neural circuits

Although memory allocation is a subject of active research in computer science, little is known about how the brain allocates information within neural circuits. There is an extensive literature on how specific types of memory engage different parts of the brain, and how neurons in these regions process and store information. Until recently, however, the mechanisms that determine how specific cells and synapses within a neural circuit (and not their neighbors) are recruited during learning have received little attention. Recent findings suggest that memory allocation is not random, but rather specific mechanisms regulate where information is stored within a neural circuit. New methods that allow tagging, imaging, activation, and inactivation of neurons in behaving animals promise to revolutionize studies of brain circuits, including memory allocation. Results from these studies are likely to have a considerable impact on computer science, as well as on the understanding of memory and its disorders.

CREB regulates excitability and the allocation of memory to subsets of neurons in the amygdala

The mechanisms that determine how information is allocated to specific regions and cells in the brain are fundamentally important for memory capacity, storage and retrieval, but are poorly understood. Here, we manipulated CREB in a subset of lateral amygdala (LA) neurons with a modified Herpes Simplex Virus (HSV), and reversibly inactivated transfected neurons with the Drosophila allatostatin G-protein-coupled receptor (AlstR)/ligand system. We found that inactivation of the HSV-CREB subpopulation of neurons with allatostatin (AL) during training disrupted memory for tone conditioning, while inactivation of a similar proportion of HSV-LacZ control neurons did not. Whole-cell recordings of fluorescently tagged HSV-CREB neurons revealed that neurons with higher CREB levels are more excitable than neighboring neurons, and show larger synaptic efficacy changes following conditioning. Our findings demonstrate that CREB modulates the allocation of fear memory to specific cells in lateral amygdala, and suggest that neuronal excitability plays a key role in this process.

Areolar discharge and peri-areolar breast cysts in adolescent females

Nipple discharge in adolescents is well documented, and usually results from endocrine dysfunction or local breast disease. Areolar discharge, however, in healthy adolescent girls is a rare finding, and is sometimes associated with peri-areolar lumps. These patients usually present with painless discharge from around the nipple, and sometimes with a lump at the site. Some patients present with a lump only, and secondary inflammation at the site can occur. Although the lesions often resolve spontaneously, they can recur, and the treatment options are discussed. There are very few cases in the literature of areolar discharge in young girls, which perhaps reflects its incidence. The following case report of 16 patients appears to be the largest collection of patients reported with this apparently benign condition. Ultrasound examination is a useful tool in the diagnosis of this condition. Fine needle aspiration was sometimes curative, but surgical excision appeared definitive therapy.