Factors Influencing Luciferase-Based Bioluminescent Imaging in Preclinical Models of Brain Tumor.

Bioluminescent imaging (BLI) is a powerful tool in biomedical research to measure gene expression and tumor growth. The current study examined factors that influence the BLI signal, specifically focusing on the tissue distribution of two luciferase substrates, D-luciferin and CycLuc1. D-luciferin, a natural substrate of firefly luciferase, has been reported to have limited brain distribution, possibly due to the efflux transporter, breast cancer resistance protein (Bcrp), at the blood-brain barrier. CycLuc1, a synthetic analog of D-luciferin, has a greater BLI signal at lower doses than D-luciferin, especially in the brain. Our results indicate that limited brain distribution of D-luciferin and CycLuc1 is predominantly dictated by their low intrinsic permeability across the cell membrane, where the efflux transporter, Bcrp, plays a relatively minor role. Both genetic ablation and pharmacological inhibition of Bcrp decreased the systemic clearance of both luciferase substrates, significantly increasing exposure in the blood and, hence, in organs and tissues. These data also indicate that the biodistribution of luciferase substrates can be differentially influenced in luciferase-bearing tissues, leading to a "tissue-dependent" BLI signal. The results of this study point to the need to consider multiple mechanisms that influence the distribution of luciferase substrates. SIGNIFICANCE STATEMENT: Bioluminescence is used to monitor many biological processes, including tumor growth. This study examined the pharmacokinetics, brain distribution, and the role of active efflux transporters on the luciferase substrates D-luciferin and CycLuc1. CycLuc1 has a more sustained systemic circulation time (longer half-life) that can provide an advantage for the superior imaging outcome of CycLuc1 over D-luciferin. The disparity in imaging intensities between brain and peripheral sites is due to low intrinsic permeability of these luciferase substrates across the blood-brain barrier.

Central Nervous System Distribution of an Opioid Agonist Combination with Synergistic Activity.

Novel combinations of specific opioid agonists like loperamide and oxymorphindole targeting the µ- and δ-opioid receptors, respectively, have shown increased potency with minimized opioid-associated risks. However, whether their interaction is pharmacokinetic or pharmacodynamic in nature has not been determined. This study quantitatively determined whether these drugs have a pharmacokinetic interaction that alters systemic disposition or central nervous system (CNS) distribution. We performed intravenous and oral in vivo pharmacokinetic assessments of both drugs after discrete dosing and administration in combination to determine whether the combination had any effect on systemic pharmacokinetic parameters or CNS exposure. Drugs were administered at 5 or 10 mg/kg i.v. or 30 mg/kg orally to institute for cancer research (ICR) mice and 5 mg/kg i.v. to Friend leukemia virus strain B mice of the following genotypes: wild-type, breast cancer resistance protein (Bcrp-/- ) (Bcrp knockout), Mdr1a/b-/- [P-glycoprotein (P-gp) knockout], and Bcrp-/- Mdr1a/b-/- (triple knockout). In the combination, clearance of oxymorphindole (OMI) was reduced by approximately half, and the plasma area under the concentration-time curve (AUC) increased. Consequently, brain and spinal cord AUCs for OMI in the combination also increased proportionately. Both loperamide and OMI are P-gp substrates, but administration of the two drugs in combination does not alter efflux transport at the CNS barriers. Because OMI alone shows appreciable brain penetration but little therapeutic efficacy on its own, and because loperamide's CNS distribution is unchanged in the combination, the mechanism of action for the increased potency of the combination is most likely pharmacodynamic and most likely occurs at receptors in the peripheral nervous system. This combination has favorable characteristics for future development. SIGNIFICANCE STATEMENT: Opioids have yet to be replaced as the most effective treatments for moderate-to-severe pain and chronic pain, but their side effects are dangerous. Combinations of opioids with peripheral activity, such as loperamide and oxymorphindole, would be valuable in that they are effective at much lower doses and have reduced risks for dangerous side effects because the µ-opioid receptor agonist is largely excluded from the CNS.

Brain Distribution of Berzosertib: An Ataxia Telangiectasia and Rad3-Related Protein Inhibitor for the Treatment of Glioblastoma.

The effective treatment of brain tumors is a considerable challenge in part because of the presence of the blood-brain barrier (BBB) that limits drug delivery. Glioblastoma multiforme (GBM) is an aggressive and infiltrative primary brain tumor with an extremely poor prognosis after standard-of-care therapy with surgery, radiotherapy (RT), and chemotherapy. DNA damage response (DDR) pathways play a critical role in DNA repair in cancer cells, and inhibition of these pathways can potentially augment RT and chemotherapy tumor cell toxicity. The ataxia telangiectasia and Rad3-related protein (ATR) kinase is a key regulator of the DDR network and is potently and selectively inhibited by the ATR inhibitor berzosertib. Although in vitro studies demonstrate a synergistic effect of berzosertib in combination with temozolomide, in vivo efficacy studies have yet to recapitulate this observation using intracranial tumor models. In the current study, we demonstrate that delivery of berzosertib to the brain is restricted by efflux at the BBB. Berzosertib has a high binding affinity to brain tissue compared with plasma, thereby leading to low free drug concentrations in the brain. Berzosertib distribution is heterogenous within the tumor, wherein concentrations are substantially lower in normal brain and invasive tumor rim (wherein the BBB is intact) when compared with those in the tumor core (wherein the BBB is leaky). These results demonstrate that high tissue binding and limited and heterogenous brain distribution of berzosertib may be important factors that influence the efficacy of berzosertib therapy in GBM. SIGNIFICANCE STATEMENT: This study examined the brain delivery and efficacy of berzosertib in patient-derived xenograft models of glioblastoma multiforme (GBM). Berzosertib is actively effluxed at the blood-brain barrier and is highly bound to brain tissue, leading to low free drug concentrations in the brain. Berzosertib is heterogeneously distributed into different regions of the brain and tumor and, in this study, was not efficacious in vivo when combined with temozolomide. These factors inform the future clinical utility of berzosertib for GBM.

Lisdexamfetamine Pharmacokinetic Comparison Between Patients Who Underwent Roux-en-Y Gastric Bypass and Nonsurgical Controls.

INTRODUCTION/PURPOSE: The objective of this research was to characterize the impact of Roux-en-Y gastric bypass (RYGB) on the pharmacokinetic properties of the pro-drug lisdexamfetamine and its active metabolite, d-amphetamine. MATERIALS AND METHODS: A case-control design was used where patients who had undergone RYGB 9-24 months prior were matched on sex, age, and body mass index (BMI) to nonsurgical controls who had no history of weight loss surgery. Each participant received a single 50 mg dose of lisdexamfetamine, and plasma samples were collected over a 24-h period following dosing. Noncompartmental analyses were used to compare pharmacokinetic measures between groups. RESULTS: There were no significant differences between the RYGB (n = 10) and NSC groups (n = 10) on sex (70% female), age (40.9 ± 9.6 vs. 41.3 ± 8.9 years), BMI (30.3 ± 5.2 vs. 31 ± 5.9 kg/m2), or ethnicity (100% vs. 80% White). The pharmacokinetic parameters between the RYGB and NCS groups were found to be equivalent for lisdexamfetamine and d-amphetamine, including maximum plasma concentration (Cmax), time to maximum plasma concentration (Tmax), and area under the plasma concentration-time curve (AUC(0-∞)). CONCLUSION: These data suggest that there is no need to routinely adjust lisdexamfetamine dosing following RYGB. However, given the potential for inter-individual differences, patients who undergo RYGB should be clinically monitored and individualized dosing strategies should be considered for concerns surrounding efficacy or toxicity.

High-dose MTX110 (soluble panobinostat) safely administered into the fourth ventricle in a nonhuman primate model.

OBJECTIVE: Chemotherapy infusions directly into the fourth ventricle may play a role in treating malignant fourth-ventricular tumors. This study tested the safety and pharmacokinetics of short-term and long-term administration of MTX110 (soluble panobinostat; Midatech Pharma) into the fourth ventricle of nonhuman primates. METHODS: Four rhesus macaque monkeys underwent posterior fossa craniectomy and catheter insertion into the fourth ventricle. In group I (n = 2), catheters were externalized and lumbar drain catheters were placed simultaneously to assess CSF distribution after short-term infusions. MTX110 (0.5 ml of 300 µM panobinostat solution) was infused into the fourth ventricle daily for 5 consecutive days. Serial CSF and serum panobinostat levels were measured. In group II (n = 2), fourth-ventricle catheters were connected to a subcutaneously placed port for subsequent long-term infusions. Four cycles of MTX110, each consisting of 5 daily infusions (0.5 ml of 300 µM panobinostat solution), were administered over 8 weeks. Animals underwent detailed neurological evaluations, MRI scans, and postmortem histological analyses. RESULTS: No neurological deficits occurred after intraventricular MTX110 infusions. MRI scans showed catheter placement within the fourth ventricle in all 4 animals, with extension to the cerebral aqueduct in 1 animal and into the third ventricle in 1 animal. There were no MRI signal changes in the brainstem, cerebellum, or elsewhere in the brains of any of the animals. Histologically, normal brain cytoarchitecture was preserved with only focal mild postsurgical changes in all animals. Panobinostat was undetectable in serum samples collected 2 and 4 hours after infusions in all samples in both groups. In group I, the mean peak panobinostat level in the fourth-ventricle CSF (6242 ng/ml) was significantly higher than that in the lumbar CSF (9 ng/ml; p < 0.0001). In group II, the mean peak CSF panobinostat level (11,042 ng/ml) was significantly higher than the mean trough CSF panobinostat level (33 ng/ml; p < 0.0001). CONCLUSIONS: MTX110 can be safely infused into the fourth ventricle in nonhuman primates at supratherapeutic doses. Postinfusion CSF panobinostat levels peak immediately in the fourth ventricle and then rapidly decrease over 24 hours. Panobinostat is detectable at low levels in CSF measured from the lumbar cistern up to 4 hours after infusions. These results will provide background data for a pilot clinical trial in patients with recurrent medulloblastoma.

Enhancing Brain Retention of a KIF11 Inhibitor Significantly Improves its Efficacy in a Mouse Model of Glioblastoma.

Glioblastoma, the most lethal primary brain cancer, is extremely proliferative and invasive. Tumor cells at tumor/brain-interface often exist behind a functionally intact blood-brain barrier (BBB), and so are shielded from exposure to therapeutic drug concentrations. An ideal glioblastoma treatment needs to engage targets that drive proliferation as well as invasion, with brain penetrant therapies. One such target is the mitotic kinesin KIF11, which can be inhibited with ispinesib, a potent molecularly-targeted drug. Although, achieving durable brain exposures of ispinesib is critical for adequate tumor cell engagement during mitosis, when tumor cells are vulnerable, for efficacy. Our results demonstrate that the delivery of ispinesib is restricted by P-gp and Bcrp efflux at BBB. Thereby, ispinesib distribution is heterogeneous with concentrations substantially lower in invasive tumor rim (intact BBB) compared to glioblastoma core (disrupted BBB). We further find that elacridar-a P-gp and Bcrp inhibitor-improves brain accumulation of ispinesib, resulting in remarkably reduced tumor growth and extended survival in a rodent model of glioblastoma. Such observations show the benefits and feasibility of pairing a potentially ideal treatment with a compound that improves its brain accumulation, and supports use of this strategy in clinical exploration of cell cycle-targeting therapies in brain cancers.

Do the existing systemic diseases overstate anaesthetic intervention during cataract surgery under local anaesthesia? An observational study to correlate the association.

CONTEXT: The objective was to study the extent of anaesthetic intervention and its association with systemic comorbidities. The secondary objectives were to estimate the prevalence of systemic comorbidities in age-related cataracts. AIMS: To determine the prevalence of systemic comorbidities in cataract surgery patients and association with anaesthesiologists' intervention. SETTINGS AND DESIGN: Prospective observational study. METHODS AND MATERIALS: The study was done inatertiary care hospital over a period of 3 months. Adult and consenting patients were included and those having sensitivity or toxic reaction to local anaesthetics, uncooperative, and paediatric patients were excluded. STATISTICAL ANALYSIS: The sample size (717) was calculated according to the formula for the finite population. The total number of patients suffering from comorbidities, adverse events during surgery, and events attended by an anesthesiologist with percentages were calculated. RESULTS: Of the 717 patients studied, comorbidities were associated with 385 (53.69%) patients; among which hypertension was most frequent and found in 174 (20.30%). As much as 113 (15.72%) patients had adverse events during surgery and required intervention by the attending anaesthesiologist in which 26 (15.72%) patients required drug administration for stabilization of condition of the patient. CONCLUSIONS: From this study, we conclude that there is a correlation between prevalent comorbidities and active intervention by the attending anaesthesiologist in patients undergoing cataract surgery.

Targeting the Blood-Brain Barrier to Prevent Sepsis-Associated Cognitive Impairment.

Sepsis is a systemic inflammatory disease resulting from an infection. This disorder affects 750 000 people annually in the United States and has a 62% rehospitalization rate. Septic symptoms range from typical flu-like symptoms (eg, headache, fever) to a multifactorial syndrome known as sepsis-associated encephalopathy (SAE). Patients with SAE exhibit an acute altered mental status and often have higher mortality and morbidity. In addition, many sepsis survivors are also burdened with long-term cognitive impairment. The mechanisms through which sepsis initiates SAE and promotes long-term cognitive impairment in septic survivors are poorly understood. Due to its unique role as an interface between the brain and the periphery, numerous studies support a regulatory role for the blood-brain barrier (BBB) in the progression of acute and chronic brain dysfunction. In this review, we discuss the current body of literature which supports the BBB as a nexus which integrates signals from the brain and the periphery in sepsis. We highlight key insights on the mechanisms that contribute to the BBB's role in sepsis which include neuroinflammation, increased barrier permeability, immune cell infiltration, mitochondrial dysfunction, and a potential barrier role for tissue non-specific alkaline phosphatase (TNAP). Finally, we address current drug treatments (eg, antimicrobials and intravenous immunoglobulins) for sepsis and their potential outcomes on brain function. A comprehensive understanding of these mechanisms may enable clinicians to target specific aspects of BBB function as a therapeutic tool to limit long-term cognitive impairment in sepsis survivors.

Brain Distribution of a Panel of Epidermal Growth Factor Receptor Inhibitors Using Cassette Dosing in Wild-Type and Abcb1/Abcg2-Deficient Mice.

Tyrosine kinase inhibitors that target the epidermal growth factor receptor (EGFR) have had success in treating EGFR-positive tumors, including non-small-cell lung cancer (NSCLC). However, developing EGFR inhibitors that can be delivered to the brain remains a challenge. To identify optimal compounds for brain delivery, eight EGFR inhibitors [afatinib, 6-[4-[(4-ethylpiperazin-1-yl)methyl]phenyl]-N-(1-phenylethyl)-7H-pyrrolo[2,3-day]pyrimidin-4-amine (AEE788), [4-(3-chloro-2-fluoroanilino)-7-methoxyquinazolin-6-yl] (2R)-2,4-dimethylpiperazine-1-carboxylate (AZD3759), erlotinib, dacomitinib, gefitinib, osimertinib, and vandetanib] were evaluated for distributional kinetics using cassette dosing with the ultimate goal of understanding the brain penetrability of compounds that share the same molecular target in an important oncogenic signaling pathway for both primary brain tumors (glioblastoma) and brain metastases (e.g., NSCLC). Cassette dosing was validated by comparing the brain-to-plasma ratios obtained from cassette-dosing to discrete-dosing studies. The brain-to-blood partition coefficients (Kp,brain) were calculated following cassette dosing of the eight EGFR inhibitors. The comparison of Kp,brain in wild-type and transporter-deficient mice confirmed that two major efflux transporters at the blood-brain barrier (BBB), P-glycoprotein and breast cancer resistance protein, play a crucial role in the brain distribution of seven out of eight EGFR inhibitors. Results show that the prediction of brain distribution based on physicochemical properties of a drug can be misleading, especially for compounds subject to extensive efflux transport. Moreover, this study informs the choice of EGFR inhibitors, i.e., determining BBB permeability combined with a known target potency, that may be effective in future clinical trials for brain tumors.

Brain Distribution and Active Efflux of Three panRAF Inhibitors: Considerations in the Treatment of Melanoma Brain Metastases.

Targeted inhibition of RAF and MEK by molecularly targeted agents has been employed as a strategy to block aberrant mitogen-activated protein kinase (MAPK) signaling in melanoma. While the use of BRAF and MEK inhibitors, either as a single agent or in combination, improved efficacy in BRAF-mutant melanoma, initial responses are often followed by relapse due to acquired resistance. Moreover, some BRAF inhibitors are associated with paradoxical activation of the MAPK pathway, causing the development of secondary malignancies. The use of panRAF inhibitors, i.e., those that target all isoforms of RAF, may overcome paradoxical activation and resistance. The purpose of this study was to perform a quantitative assessment and evaluation of the influence of efflux mechanisms at the blood-brain barrier (BBB), in particular, Abcb1/P-glycoprotein (P-gp) and Abcg2/breast cancer resistance protein (Bcrp), on the brain distribution of three panRAF inhibitors: CCT196969 [1-(3-(tert-butyl)-1-phenyl-1H-pyrazol-5-yl)-3-(2-fluoro-4-((3-oxo-3,4-dihydropyrido[2,3-b]pyrazin-8-yl)oxy)phenyl)urea], LY3009120 1-(3,3-Dimethylbutyl)-3-(2-fluoro-4-methyl-5-(7-methyl-2-(methylamino)pyrido(2,3-d)pyrimidin-6-yl)phenyl)urea, and MLN2480 [4-pyrimidinecarboxamide, 6-amino-5-chloro-N-[(1R)-1-[5-[[[5-chloro-4-(trifluoromethyl)-2-pyridinyl]amino]carbonyl]-2-thiazolyl]ethyl]-]. In vitro studies using transfected Madin-Darby canine kidney II cells indicate that only LY3009120 and MLN2480 are substrates of Bcrp, and none of the three inhibitors are substrates of P-gp. The three panRAF inhibitors show high nonspecific binding in brain and plasma. In vivo studies in mice show that the brain distribution of CCT196969, LY3009120, and MLN2480 is limited, and is enhanced in transgenic mice lacking P-gp and Bcrp. While MLN2480 has a higher brain distribution, LY3009120 exhibits superior in vitro efficacy in patient-derived melanoma cell lines. The delivery of a drug to the site of action residing behind a functionally intact BBB, along with drug potency against the target, collectively play a critical role in determining in vivo efficacy outcomes.

Permeability changes and effect of chemotherapy in brain adjacent to tumor in an experimental model of metastatic brain tumor from breast cancer.

BACKGROUND: Brain tumor vasculature can be significantly compromised and leakier than that of normal brain blood vessels. Little is known if there are vascular permeability alterations in the brain adjacent to tumor (BAT). Changes in BAT permeability may also lead to increased drug permeation in the BAT, which may exert toxicity on cells of the central nervous system. Herein, we studied permeation changes in BAT using quantitative fluorescent microscopy and autoradiography, while the effect of chemotherapy within the BAT region was determined by staining for activated astrocytes. METHODS: Human metastatic breast cancer cells (MDA-MB-231Br) were injected into left ventricle of female NuNu mice. Metastases were allowed to grow for 28 days, after which animals were injected fluorescent tracers Texas Red (625 Da) or Texas Red dextran (3 kDa) or a chemotherapeutic agent 14C-paclitaxel. The accumulation of tracers and 14C-paclitaxel in BAT were determined by using quantitative fluorescent microscopy and autoradiography respectively. The effect of chemotherapy in BAT was determined by staining for activated astrocytes. RESULTS: The mean permeability of texas Red (625 Da) within BAT region increased 1.0 to 2.5-fold when compared to normal brain, whereas, Texas Red dextran (3 kDa) demonstrated mean permeability increase ranging from 1.0 to 1.8-fold compared to normal brain. The Kin values in the BAT for both Texas Red (625 Da) and Texas Red dextran (3 kDa) were found to be 4.32 ± 0.2 × 105 mL/s/g and 1.6 ± 1.4 × 105 mL/s/g respectively and found to be significantly higher than the normal brain. We also found that there is significant increase in accumulation of 14C-Paclitaxel in BAT compared to the normal brain. We also observed animals treated with chemotherapy (paclitaxel (10 mg/kg), erubilin (1.5 mg/kg) and docetaxel (10 mg/kg)) showed activated astrocytes in BAT. CONCLUSIONS: Our data showed increased permeation of fluorescent tracers and 14C-paclitaxel in the BAT. This increased permeation lead to elevated levels of activated astrocytes in BAT region in the animals treated with chemotherapy.

Investigational chemotherapy and novel pharmacokinetic mechanisms for the treatment of breast cancer brain metastases.

In women, breast cancer is the most common cancer diagnosis and second most common cause of cancer death. More than half of breast cancer patients will develop metastases to the bone, liver, lung, or brain. Breast cancer brain metastases (BCBM) confers a poor prognosis, as current therapeutic options of surgery, radiation, and chemotherapy rarely significantly extend life and are considered palliative. Within the realm of chemotherapy, the last decade has seen an explosion of novel chemotherapeutics involving targeting agents and unique dosage forms. We provide a historical overview of BCBM chemotherapy, review the mechanisms of new agents such as poly-ADP ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, phosphatidyl inositol 3-kinaseinhibitors, estrogen pathway antagonists for hormone-receptor positive BCBM; tyrosine kinase inhibitors, antibodies, and conjugates for HER2+ BCBM; repurposed cytotoxic chemotherapy for triple negative BCBM; and the utilization of these new agents and formulations in ongoing clinical trials. The mechanisms of novel dosage formulations such as nanoparticles, liposomes, pegylation, the concepts of enhanced permeation and retention, and drugs utilizing these concepts involved in clinical trials are also discussed. These new treatments provide a promising outlook in the treatment of BCBM.

Liposomal Irinotecan Accumulates in Metastatic Lesions, Crosses the Blood-Tumor Barrier (BTB), and Prolongs Survival in an Experimental Model of Brain Metastases of Triple Negative Breast Cancer.

PURPOSE: The blood-tumor barrier (BTB) limits irinotecan distribution in tumors of the central nervous system. However, given that the BTB has increased passive permeability we hypothesize that liposomal irinotecan would improve local exposure of irinotecan and its active metabolite SN-38 in brain metastases relative to conventional irinotecan due to enhanced-permeation and retention (EPR) effect. METHODS: Female nude mice were intracardially or intracranially implanted with human brain seeking breast cancer cells (brain metastases of breast cancer model). Mice were administered vehicle, non-liposomal irinotecan (50 mg/kg), liposomal irinotecan (10 mg/kg and 50 mg/kg) intravenously starting on day 21. Drug accumulation, tumor burden, and survival were evaluated. RESULTS: Liposomal irinotecan showed prolonged plasma drug exposure with mean residence time (MRT) of 17.7 ± 3.8 h for SN-38, whereas MRT was 3.67 ± 1.2 for non-liposomal irinotecan. Further, liposomal irinotecan accumulated in metastatic lesions and demonstrated prolonged exposure of SN-38 compared to non-liposomal irinotecan. Liposomal irinotecan achieved AUC values of 6883 ± 4149 ng-h/g for SN-38, whereas non-liposomal irinotecan showed significantly lower AUC values of 982 ± 256 ng-h/g for SN-38. Median survival for liposomal irinotecan was 50 days, increased from 37 days (p<0.05) for vehicle. CONCLUSIONS: Liposomal irinotecan accumulates in brain metastases, acts as depot for sustained release of irinotecan and SN-38, which results in prolonged survival in preclinical model of breast cancer brain metastasis.

Detection of Plasmid Mediated AmpC-ß lactamases Among Gram-Negative Uropathogens at a Tertiary Care Hospital, Dhaka City.

Plasmid-mediated AmpC ß-lactamase (PMABL) resistance among gram negative bacilli is an emerging problem worldwide. They likely originate from chromosomal AmpC of certain Gram-negative bacterial species and subsequently are mobilized to transmissible plasmids. There are reports of unfavorable clinical outcomes in patients infected with these organisms and treated with broad-spectrumcephalosporins. The present cross sectional study was designed to detect PMABL genes among gram negative uropathogens in a tertiary care hospital, Dhaka city, Bangladesh from January 2014 to December 2014. Total 138 gram negative uropathogens were identified by the conventional methods and were screened for AmpC production using cefoxitin discs. Confirmatory phenotypic identification was done by modified three dimensional test (MTDT). The common AmpC genotypes ACC, FOX, MOX, DHA, CIT and EBC types were determined by a multiplex PCR.PMABL genes were detected by PCR in 90% of cefoxitin resistant isolates and the molecular types of the genes detected predominantly were CIT, DHA followed by EBC and ACC types. Overall, PMABL genes were detected in 32.61% (45/138) of the studied gram negative uropathogens which is alarming. All (100%) the plasmid mediated AmpC ß-lactamase producers showed resistance to amoxicillin-clavulanic acid, ceftazidime, ceftriaxone, cefotaxime and cefoxitin. These results emphasize that clinical laboratories should consider the tests for the detection of PMABL genes for infection control and formulation of effective antibiotic policy.

Addison's Disease: A Diagnostic Dilemma.

Adrenal insufficiency is a rare disease, but is life threatening when overlooked. Addison's disease may be an acquired form of adrenal insufficiency due to the destruction or dysfunction of the adrenal cortex. It affects both glucocorticoid and mineralocorticoid function. Main presenting symptoms of Addison's disease such as fatigue, anorexia, vomiting and convulsion often mimics central nervous system (CNS) infections. We describe a case of Addison's disease who was initially misdiagnosed as a case of meningo-encephalitis subsequently renal tubular acidosis and finally Addison's disease. Addison's disease can remain unrecognized until acute crisis and sometimes it may be misdiagnosed.

A mouse Model of Focal Vascular Injury Induces Astrocyte Reactivity, Tau Oligomers, and Aberrant Behavior.

Neuropsychiatric symptom development has become more prevalent with 270,000 blast exposures occurring in the past 10 years in the United States. How blast injury leads to neuropsychiatric symptomology is currently unknown. Preclinical models of blast-induced traumatic brain injury have been used to demonstrate blood-brain barrier disruption, degenerative pathophysiology, and behavioral deficits. Vascular injury is a primary effect of neurotrauma that can trigger secondary injury cascades and neurodegeneration. Here we present data from a novel scaled and clinically relevant mouse blast model that was specifically developed to assess the outcome of vascular injury. We look at the biochemical effects and behavioral changes associated with blast injury in young-adult male BALB/c mice. We report that blast exposure causes focal vascular injury in the Somatosensory Barrel Field cortex, which leads to perivascular astrocyte reactivity, as well as acute aberrant behavior. Biochemical analysis revealed that mild blast exposure also invokes tauopathy, neuroinflammation, and oxidative stress. Overall, we propose our model to be used to evaluate focal blood-brain barrier disruption and to discover novel therapies for human neuropsychiatric symptoms.

Role of pRIFLE Criteria in Early Diagnosis of Severity Staging of Neonatal AKI and its Impact on Management.

Mortality is high among sick neonates who have concomitant acute kidney injury (AKI). This observational study was done at Special Care Baby Unit (SCABU) of Dhaka Medical College Hospital (DMCH), Bangladesh from October 2013 to March 2014 to find out the role of pRIFLE criteria in prediction of severity stages of AKI in neonate and early intervention to see the immediate outcome. A total of 44 neonates with AKI were included, all were treated conservatively and with intermittent peritoneal dialysis (IPD) as needed. The neonate of ≤7 days old comprised the main bulk (n=28) and M: F = 21: 23. The diagnosis was based on eCCL criteria of pRIFLE showed that 40.9% neonates were at risk of AKI, 20.5% have had already injured. Higher proportions of neonates were classified as failure (38.6%). The distribution of biochemical parameters among three stages of AKI showed serum potassium was significantly higher in failure group (p<0.001). The serum creatinine both at baseline and at next evaluations were significantly raised in the failure group (p<0.001). However, failure group had a significantly longer hospital stay compared to risk and injury group (p<0.001). Multiorgan failure was found to be lower in the risk group compared to other two groups (p=0.026). Majority of the failure group needed dialysis as compared to the risk and injury group (p<0.001). The mortality was progressively higher from risk to failure groups (p=0.106). Overall 27% of the neonates diagnosed AKI by pRIFLE were died of the disease. The study concluded that pRIFLE staging in AKI is useful and sensitive in the diagnosis and management of AKI in neonates.

Quantitative Fluorescence Microscopy Measures Vascular Pore Size in Primary and Metastatic Brain Tumors.

Tumors residing in the central nervous system (CNS) compromise the blood-brain barrier (BBB) via increased vascular permeability, with the magnitude of changes dependent on the tumor type and location. Current studies determine penetrability of a cancer therapeutic by administering progressively larger molecules until cutoff is observed where little to no tumor accumulation occurs. However, decades-old experimental work and mathematical modeling document methods to calculate both the size of the vascular opening (pore) with solute permeability values. In this study, we updated this classic mathematical modeling approach with quantitative fluorescence microscopy in two preclinical tumor models, allowing simultaneous administration of multiple sized tracers to determine vascular permeability at a resolution of nearly one micron. We observed that three molecules ranging from 100 Da to 70 kDa permeated into a preclinical glioblastoma model at rates proportional to their diffusion in water. This suggests the solutes freely diffused from blood to glioma across vascular pores without steric restriction, which calculates to a pore size of >140 nm in diameter. In contrast, the calculated pore size of a brain metastasis of breast cancer was approximately 10-fold smaller than glioma vasculature. This difference explains why antibodies are effective against glioblastoma but generally fail in brain metastases of breast cancer. On the basis of our observations, we hypothesize that trastuzumab most likely fails in the treatment of brain metastases of breast cancer because of poor CNS penetration, while the similar sized antibody bevacizumab is effective in the same tumor type not because it penetrates the CNS degree better, but because it scavenges VEGF in the vascular compartment, which reduces edema and permeation. Cancer Res; 77(2); 238-46. ©2016 AACR.

Health Related Quality of Life in Children with Nephrotic Syndrome in Bangladesh.

Outcome of children with nephrotic syndrome has continued to improve over time. However minimal data exist to describe health-related quality of life in children with nephrotic syndrome. This cross sectional study was conducted over a period of six months to assess the health related quality of life in children with nephrotic syndrome in the Department of Pediatric Nephrology, Dhaka Medical College Hospital, Bangladesh. Fifty children (age ranged 2-12 years) with nephrotic syndrome who had three or more relapses diagnosed at least one year back receiving treatment and on follow up were included in this study. Quality of Life scores were collected using Bengali translated instruments- the Pediatric Quality of Life Inventory™ (PedsQL™) version 4.0 Generic Scale and the Pediatric Quality of Life Questionnaire for Nephrotic Syndrome proxy-report from parents. Medical data and Demographic data were collected from medical records, and from parents in outpatient department or hospital ward. Interviews of eligible guardians were performed individually to collect quality of life (QoL) scores. Among 50 children, mean±SD age of the children was 7±2.92 years. Most children were male (58%). Female parents respondent during interview were 62%, most parents (48%) were very poor in socioeconomic condition. Most children had frequent relapses (60%). Median time since diagnosis was 2 years. Regarding PedsQL scores, child age with physical summary score (p value <0.001), child age with social summary score (p value 0.003), frequent relapse with kidney disease summary score (p value 0.04) and time since diagnosis (p value <0.001) were statistically significant. In conclusion physical and social summary score were worst. Frequent relapse found to be an important factor in impaired QoL. Prolonged duration of the disease activity was associated with significant impairment of QoL.

Experience of Percutaneous Versus Surgically Placed Catheter for Continuous Ambulatory Peritoneal Dialysis in Children with Chronic Kidney Disease Stage-V.

The lifespan and outcome of end stage renal disease (ESRD) children have dramatically improved since the development of continuous ambulatory peritoneal dialysis (CAPD), it offers several advantages over hemodialysis. Percutaneous placement of CAPD catheters in children is minimally invasive, reliable, safe and cost-effective method. Percutaneous method of CAPD catheter insertion can be used in children to avoid the complications of general anesthesia and surgery. This study was done to evaluate the efficacy of CAPD in children, to find out the complication profile of CAPD & to compare the advantages of surgical versus percutaneously placed CAPD catheters in children. This prospective longitudinal comparative study was carried out in the department of Pediatric Nephrology, Dhaka Medical College Hospital (DMCH), Bangladesh from July 2011 to June 2014. A total of 8 children with ESRD were included (Age 5-14 year, M: F=1: 1). All underwent CAPD, Group I = surgically placed CAPD catheter (N=5), Group II = percutaneously placed CAPD catheter (N=3). Average duration of CAPD in Group I and Group II were 31.6 vs. 9 (months) with a total of 158 vs. 27 patient months of CAPD respectively. The rate of complications of the 2 groups and their outcome were compared. Common complications being observed were peritonitis 1 episode per 12.1 vs. 1.8 patient months (p<0.001), catheter obstruction by omental capture 1 vs. 3 in Group I and Group II respectively. Catheter tip dislocation was commonly found in all Group II children (p<0.01) and all needed laparotomy and omentectomy. Three out of 5 in Group I is still on CAPD, 1 transferred to HD and another 1 expired due to uncontrolled hypertension with congestive heart failure. Among 3 of Group II, 2 died of repeated peritonitis and hypertensive complications and rest 1 is transferred to HD after 1year due to exit site fluid leaking. Satisfactory level of improvement of mean weight, mean serum albumin and declining of serum creatinine in both groups has been found after CAPD. Although CAPD is an effective modality of renal replacement therapy for children, but percutaneous method of catheter insertion is associated with higher rate of complications. Placement of catheter by surgical method with elective omentectomy will reduce catheter related complications. Early detection of peritonitis and prompt therapy is essential for a favourable outcome.