MRI-guided pulsed focused ultrasound (pFUS) combined with systemic infusion of ultrasound contrast agent microbubbles (MB) causes localized blood-brain barrier (BBB) disruption that is currently being advocated for increasing drug or gene delivery in neurological diseases. The mechanical acoustic cavitation effects of opening the BBB by low-intensity pFUS+MB, as evidenced by contrast-enhanced MRI, resulted in an immediate damage-associated molecular pattern (DAMP) response including elevations in heat-shock protein 70, IL-1, IL-18, and TNFα indicative of a sterile inflammatory response (SIR) in the parenchyma. Concurrent with DAMP presentation, significant elevations in proinflammatory, antiinflammatory, and trophic factors along with neurotrophic and neurogenesis factors were detected; these elevations lasted 24 h. Transcriptomic analysis of sonicated brain supported the proteomic findings and indicated that the SIR was facilitated through the induction of the NFκB pathway. Histological evaluation demonstrated increased albumin in the parenchyma that cleared by 24 h along with TUNEL + neurons, activated astrocytes, microglia, and increased cell adhesion molecules in the vasculature. Infusion of fluorescent beads 3 d before pFUS+MB revealed the infiltration of CD68 + macrophages at 6 d postsonication, as is consistent with an innate immune response. pFUS+MB is being considered as part of a noninvasive adjuvant treatment for malignancy or neurodegenerative diseases. These results demonstrate that pFUS+MB induces an SIR compatible with ischemia or mild traumatic brain injury. Further investigation will be required before this approach can be widely implemented in clinical trials.pulsed focused ultrasound | microbubbles | blood-brain barrier | sterile inflammation | magnetic resonance imaging T he temporal proteomic profile in response to blood-brain barrier disruption (BBBD) consists of molecular features that are common across noninfectious insults such as ischemia, trauma, or autoimmune diseases (1-7). The main purpose of the bloodbrain barrier (BBB) is to maintain homeostasis, preventing the passive crossing of cells and molecules that could induce inflammation or damage to cells. The BBB consists of specialized endothelial cells connected through various tight junction proteins (TJP), astrocyte endplates, and a basement membrane. These components form part of the neurovascular unit (NVU) that is comprised of vessels, pericytes, microglia, astrocytes, and neurons along with the extracellular matrix (1,3,4,8). BBBD secondary to ischemia or trauma leads to increases in endothelial caveolae and down-regulation of TJP, transcytosis of plasma proteins (i.e., albumin), and vasogenic edema (1,6,(8)(9)(10)(11). The presence of albumin in the parenchyma following BBBD can activate astrocytes and microglia and induce the production of cytokines, chemokines, and trophic factors (CCTFs) and cell adhesion molecules (CAMs) as observed with a sterile inflammatory response (SIR) to injury (12-15). The release of CCTFs and inte...

Magnetic resonance imaging (MRI)-guided pulsed focused ultrasound (pFUS) combined with microbubbles (MB) contrast agent infusion has been shown to transiently disrupt the blood-brain barrier (BBBD), increasing the delivery of neurotherapeutics to treat central nervous system (CNS) diseases. pFUS interaction with the intravascular MB results in acoustic cavitation forces passing through the neurovascular unit (NVU), inducing BBBD detected on contrast-enhanced MRI. Multiple pFUS+MB exposures in Alzheimer's disease (AD) models are being investigated as a method to clear amyloid plaques by activated microglia or infiltrating immune cells. Since it has been reported that pFUS+MB can induce a sterile inflammatory response (SIR) [1-5] in the rat, the goal of this study was to investigate the potential long-term effects of SIR in the brain following single and six weekly sonications by serial high-resolution MRI and pathology.Methods: Female Sprague Dawley rats weighing 217±16.6 g prior to sonication received bromo-deoxyuridine (BrdU) to tag proliferating cells in the brain. pFUS was performed at 548 kHz, ultrasound burst 10 ms and initial peak negative pressure of 0.3 MPa (in water) for 120 s coupled with a slow infusion of ~460 µL/kg (5-8×107 MB) that started 30 s before and 30 s during sonication. Nine 2 mm focal regions in the left cortex and four regions over the right hippocampus were treated with pFUS+MB. Serial high-resolution brain MRIs at 3 T and 9.4 T were obtained following a single or during the course of six weekly pFUS+MB resulting in BBBD in the left cortex and the right hippocampus. Animals were monitored over 7 to 13 weeks and imaging results were compared to histology.Results: Fewer than half of the rats receiving a single pFUS+MB exposure displayed hypointense voxels on T2*-weighted (w) MRI at week 7 or 13 in the cortex or hippocampus without differences compared to the contralateral side on histograms of T2* maps. Single sonicated rats had evidence of limited microglia activation on pathology compared to the contralateral hemisphere. Six weekly pFUS+MB treatments resulted in pathological changes on T2*w images with multiple hypointense regions, cortical atrophy, along with 50% of rats having persistent BBBD and astrogliosis by MRI. Pathologic analysis of the multiple sonicated animals demonstrated the presence of metallophagocytic Prussian blue-positive cells in the parenchyma with significantly (p<0.05) increased areas of activated astrocytes and microglia, and high numbers of systemic infiltrating CD68+ macrophages along with BrdU+ cells compared to contralateral brain. In addition, multiple treatments caused an increase in the number of hyperphosphorylated Tau (pTau)-positive neurons containing neurofibrillary tangles (NFT) in the sonicated cortex but not in the hippocampus when compared to contralateral brain, which was confirmed by Western blot (WB) (p<0.04).Conclusions: The repeated SIR following multiple pFUS+MB treatments could contribute to changes on MR imaging including persistent BBBD, co...

Neither author has a financial or proprietary interest in any material or method mentioned.

In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca2+]i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca2+]i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48-hours to a variety of stressors: cytokines (low-grade inflammation), 28mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca2+]i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca2+]i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3-to-11mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca2+]i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11mM:3mM glucose) observed for FFAs and also for 28G. We also clamped [Ca2+]i using 30mM KCl + 250uM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3-to-11mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca2+]i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca2+]i but not conventional insulin secretion and ‘metabolic’ stressors (FFAs, 28G, rotenone) impacted insulin secretion.

Endocrine cells of the pancreatic islet interact with their microenvironment to maintain tissue homeostasis. Communication with local macrophages is particularly important in this context, but the homeostatic functions of human islet macrophages are not known. In this study, we show that the human islet contains macrophages in perivascular regions that are the main local source of the anti-inflammatory cytokine interleukin-10 (IL-10) and the metalloproteinase MMP9. Macrophage production and secretion of these homeostatic factors are controlled by endogenous purinergic signals. In obese and diabetic states, macrophage expression of purinergic receptors MMP9 and IL-10 is reduced. We propose that in those states, exacerbated b-cell activity due to increased insulin demand and increased cell death produce high levels of ATP that downregulate purinergic receptor expression. Loss of ATP sensing in macrophages may reduce their secretory capacity.

Background and Objective:Children spend most of their time in schools and are vulnerable to injuries and mild ailments, hence requiring first-aid care. School teacher can provide immediate first-aid care in the absence of any health professional. This study assesses first-aid facilities within school premises and assessment of teachers on first aid training.Methods:A cross sectional study was conducted from July-December 2017, participants were full time school teachers of both public and private sectors at both primary and secondary levels, having a minimum of one year experience. Questionnaire was filled on one to one basis by taking oral interview.Results:Out of 209 teachers, 72.7% were from private sector. Stomachache was the most common medical incident (82.29%) requiring first-aid care in schools. First aid box was available in all schools but its contents were not satisfactory. Sick bay was not found in any school. 68.42% of teachers were not trained in first-aid management because of lack of opportunity, however 56% were willing to enroll in any first aid training and majority (91.38%) considered it essential for their professional life.Conclusion:First aid facilities at various schools of Karachi and availability of trained teachers who can provide first aid care is unsatisfactory.

The referral pathway of patients with retinal detachment from primary care providers to a tertiary care ophthalmic unit was examined, in order to determine the length and source of any delays between the onset of symptoms and arrival at the hospital. A prospective survey of all symptomatic patients (n = 60) admitted for primary rhegmatogenous retinal detachment surgery was carried out over an 8 week period. Twenty-one patients were referred by their optometrists and 18 by their general practitioners. The remainder were referred by local accident and emergency and ophthalmic departments or presented directly to the tertiary referral centre. Patients who presented to their optometrists were symptomatic for an average of four times longer. More than half the patients thought that the time to initial presentation was the most significant delay. Referral from optometrists via general practitioners and local ophthalmic clinics was considerably longer. Increased awareness of symptoms, necessity of urgent referral and knowledge of available services locally may reduce delay for those who require emergency sight-saving surgery.

Intra-vitreal anti-VEGF injections with volumes of 0.05  ml appears to produce displacement of the conjunctiva with a transient fluid-filled bleb immediately after the injection in approximately 1/3 of eyes.