Pediatric Atypical Hemolytic Uremic Syndrome Advances

Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by dysregulation of the alternate pathway. The diagnosis of aHUS is one of exclusion, which complicates its early detection and corresponding intervention to mitigate its high rate of mortality and associated morbidity. Heterozygous mutations in complement regulatory proteins linked to aHUS are not always phenotypically active, and may require a particular trigger for the disease to manifest. This list of triggers continues to expand as more data is aggregated, particularly centered around COVID-19 and pediatric vaccinations. Novel genetic mutations continue to be identified though advancements in technology as well as greater access to cohorts of interest, as in diacylglycerol kinase epsilon (DGKE). DGKE mutations associated with aHUS are the first non-complement regulatory proteins associated with the disease, drastically changing the established framework. Additional markers that are less understood, but continue to be acknowledged, include the unique autoantibodies to complement factor H and complement factor I which are pathogenic drivers in aHUS. Interventional therapeutics have undergone the most advancements, as pharmacokinetic and pharmacodynamic properties are modified as needed in addition to their as biosimilar counterparts. As data continues to be gathered in this field, future advancements will optimally decrease the mortality and morbidity of this disease in children.

Lipid A-Ara4N as an alternate pathway for (colistin) resistance in Klebsiella pneumonia isolates in Pakistan

Objectives This study aimed to explore mechanism of colistin resistance amongst Klebsiella pneumoniae isolates through plasmid mediated mcr-1 gene in Pakistan. Carbapenem and Colistin resistant K. pneumoniae isolates (n = 34) stored at − 80 °C as part of the Aga Khan University Clinical Laboratory strain bank were randomly selected and subjected to mcr-1 gene PCR. To investigate mechanisms of resistance, other than plasmid mediated mcr-1 gene, whole genome sequencing was performed on 8 clinical isolates, including 6 with colistin resistance (MIC > 4 μg/ml) and 2 with intermediate resistance to colistin (MIC > 2 μg/ml). Results RT-PCR conducted revealed absence of mcr-1 gene in all isolates tested. Whole genome sequencing results revealed modifications in Lipid A-Ara4N pathway. Modifications in Lipid A-Ara4N pathway were detected in ArnA_ DH/FT, UgdH, ArnC and ArnT genes. Mutation in ArnA_ DH/FT gene were detected in S3, S5, S6 and S7 isolates. UgdH gene modifications were found in all isolates except S3, mutations in ArnC were present in all except S1, S2 and S8 and ArnT were detected in all except S4 and S7. In the absence of known mutations linked with colistin resistance, lipid pathway modifications may possibly explain the phenotype resistance to colistin, but this needs further exploration.

Road to becoming Y-90 authorized user as an integrated vascular and interventional radiology resident (NRC alternate pathway)

Yttrium-90 (Y-90) radioembolization, also called transarterial radioembolization (TARE), is a catheter-directed therapy for direct delivery of internal radiation to tumors in the form of microspheres. It is currently available in two forms, either as a constituent of glass microspheres called TheraSphere® (BTG Ltd., London, UK [now Boston Scientific, Marlborough, MA, USA]) or as a biocompatible resin-based microsphere called SIR-Spheres® (Sirtex Medical Ltd., Woburn, MA, USA). Once these microspheres are delivered to the tumor through an arterial pathway, they are embedded within the tumor microcirculation and emit β-radiation at therapeutic levels. TARE is a commonly used treatment for unresectable primary or secondary hepatic malignancies and has led to improved survival rates and increased success rates in downstaging patients before liver resection or transplantation. Immediately following the pre-treatment angiogram, each patient undergoes a nuclear medicine study, otherwise known as technetium (99mTc) macroaggregated albumin scan, to determine the amount of radiotracer that has accumulated in the lungs (lung shunt fraction). Finally, after several calculations, the appropriate radiation dose to be delivered to the tumor is determined. While the technical aspects of radioembolization are quite complex, the collective clinical experience presented in the literature supports the use of Y-90 radioembolization for unresectable hepatic malignancies. Those ordering and administering radioembolization particles must be deemed an authorized user (AU) by the Nuclear Regulatory Commission (NRC). The NRC defines an AU as the individual responsible for ensuring that radioactive materials are handled and used safely and following NRC regulations and the terms and conditions of the NRC license. The NRC has published licensing guidance on Y-90 brachytherapy with the 10th revision released on November 8, 2019. This guidance has outlined specific requirements for obtaining a license for the use of TheraSphere and SIR-Spheres. Following the revised licensure guidelines from the NRC on Y-90 usage, a conditional authorization has been obtained at our institution by the PGY-6 interventional radiology/diagnostic radiology (IR/DR) resident. While the full guidelines and extensive alternative requirements can be found online, we will highlight the specific guidelines applicable to and fulfilled by IR/DR residents. The traditional ABR pathway takes approximately 18 months after graduation, including passing the ABR certification examination to become an AU. With the proposed alternate pathway, trainees will potentially become AU immediately after graduation. The primary aim of this submission is to describe the process for obtaining conditional authorization for Y-90 microspheres for PGY-6 IR/DR residents.

GlmS mediated knock-down of a phospholipase expedite alternate pathway to generate phosphocholine required for phosphatidylcholine synthesis in Plasmodium falciparum

Phospholipid synthesis is crucial for membrane proliferation in malaria parasites during the entire cycle in the host cell. The major phospholipid of parasite membranes, phosphatidylcholine (PC), is mainly synthesized through the Kennedy pathway. The phosphocholine required for this synthetic pathway is generated by phosphorylation of choline derived from catabolism of the lyso-phosphatidylcholine (LPC) scavenged from the host milieu. Here we have characterized a Plasmodium falciparum lysophospholipase (PfLPL20) which showed enzymatic activity on LPC substrate to generate choline. Using GFP- targeting approach, PfLPL20 was localized in vesicular structures associated with the neutral lipid storage bodies present juxtaposed to the food-vacuole. The C-terminal tagged glmS mediated inducible knock-down of PfLPL20 caused transient hindrance in the parasite development, however, the parasites were able to multiply efficiently, suggesting that PfLPL20 is not essential for the parasite. However, in PfLPL20 depleted parasites, transcript levels of enzyme of SDPM pathway (Serine Decarboxylase-Phosphoethanolamine Methyltransferase) were altered along with upregulation of phosphocholine and SAM levels; these results show upregulation of alternate pathway to generate the phosphocholine required for PC synthesis through the Kennedy pathway. Our study highlights presence of alternate pathways for lipid homeostasis/membrane-biogenesis in the parasite; these data could be useful to design future therapeutic approaches targeting phospholipid metabolism in the parasite.

A Comprehensive Mini Review on Co-Crystallization Process

Co‑crystal chemistry has recently attracted supramolecular scientists. Co-crystals are comprising of hydrogen bonding assembly between different molecules. Many issues related to the performance characteristics of an active pharmaceutical ingredient (API) can be resolved using the co-crystallization approach. A proper understanding of the crystal structure of an API is required for the successful formation of co-crystals with the selected co‑former. Co-crystal chemistry has recently attracted scientists from the super molecules. Co crystals consist of the assembly of hydrogen bonds between various molecules. Many problems related to the performance characteristics of an active pharmaceutical ingredient (API) can be solved using the method of co-crystallization. Co-Crystals offer an alternate pathway where any API, paying little mind to be acidic, essential, or ionizable gatherings, might be co-gem. This aspect also helps to complement existing methods by reintroducing molecules with limited pharmaceutical profiles based on their non-ionizable functional groups.