Structure-guided stabilization improves the ability of the HIV-1 gp41 hydrophobic pocket to elicit neutralizing antibodies

The hydrophobic pocket found in the N-heptad repeat (NHR) region of HIV-1 gp41 is a highly conserved epitope that is the target of various HIV-1-neutralizing monoclonal antibodies. Although the high conservation of the pocket makes it an attractive vaccine candidate, it has been challenging to elicit potent anti-NHR antibodies via immunization. Here, we solved a high-resolution structure of the NHR mimetic IQN17, and, consistent with previous ligand-bound gp41 pocket structures, we observed remarkable conformational plasticity of the pocket. The high malleability of this pocket led us to test whether we could improve the immunogenicity of the gp41 pocket by stabilizing its conformation. We show that the addition of five amino acids at the C terminus of IQN17, to generate IQN22, introduces a stabilizing salt bridge at the base of the peptide that rigidifies the pocket. Mice immunized with IQN22 elicited higher avidity antibodies against the gp41 pocket and a more potent, albeit still weak, neutralizing response against HIV-1 compared with IQN17. Stabilized epitope-focused immunogens could serve as the basis for future HIV-1 fusion-inhibiting vaccines.

Abstract 2706: Ultra-Low Input High-Fidelity (ULI-HiFi) long-reads uncover variants in genomic dark matter from pre-cancer polyp and tumor samples

Long-read sequencing technologies have been constrained by high error rates and large sample input requirements. The recent introduction of HiFi sequencing has enabled highly accurate detection of single-nucleotide variants (SNVs) from long reads (10-15 kb). However, a major limiting factor is the amount of sample input required, where current protocols require ≥15 micrograms of DNA. Here we report Ultra-Low Input High Fidelity Sequencing (ULI-HiFi), an amplification-based library preparation that reduces this input to 10 nanograms of DNA, a more than 10,000-fold reduction in sample input. When the ultra-low input method was tested using a benchmark genome, HG002, we observed high precision and improved recall of structural variants compared to a ground truth dataset from the Genome in a Bottle Consortium. We also benchmarked small variants and reported the accurate analysis of many variants in clinically important genes that are unmappable with short reads. We used this strategy to sequence tumor and polyp samples from a patient with familial adenomatous polyposis, a hereditary form of colon cancer, which revealed SNVs and structural variants not detected by short-read techniques. This strategy will enable the improved characterization of genetic variants from limited clinical samples.

Citation Format: Hayan Lee, Graham Erwin, Aaron Horning, Raushun Kirtikar, Emmett Griffin-Baldwin, William Rowell, Philip Li, Sarah Kingan, Michael P. Snyder. Ultra-Low Input High-Fidelity (ULI-HiFi) long-reads uncover variants in genomic dark matter from pre-cancer polyp and tumor samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2706.

Carotid artery ectasia coexistent with primary open angle glaucoma

A 60-year-old smoker presented with high intraocular pressure in the right eye with a right afferent pupil defect and visual field suggestive of primary open angle glaucoma in the right eye only, when an examination 2 years earlier had revealed no hint of ocular pathology. Radiological investigations demonstrated prominent ectasia of the internal carotid arteries extending into the proximal middle cerebral arteries. The changes in the carotids extended throughout the cavernous sinus regions, encroached on the under surface of the optic chiasm and were closely related to the internal aspects of both optic canals. In primary open angle glaucoma management, neural imaging is not normally recommended; however, neural imaging investigations should be considered if the presentation is not typical of a chronic bilateral optic neuropathy

Drug use and prescribing problems in four state Medicaid programs

In this article the authors present population-level prevalence rates for 61 specific drug-related problems occurring in three State Medicaid programs (Maryland, Iowa, and Washington) from 1989 through 1996 and a fourth (Georgia) from 1994 through 1996. The findings represent the first application of a consistent drug utilization review (DUR) screener program to Medicaid data across States. The study finds major differences in DUR failure rates among the four States with the lowest rates in Georgia and the highest in Washington. Only Iowa showed any population-level reduction in DUR failure rates during the study period, however, rates for community-dwelling elderly fell in most States.

Epidemiology of common transmissible skin diseases among primary school children in north-west Ethiopia

A total of 1842 school children were examined for the occurrence of common transmissible skin infections in a rural area in North-West Ethiopia. The result showed a prevalence rate of 49.2%. Tinea capitis, impetigo, infected wounds and verrucae vulgaris were common. In addition the overall prevalence rate of lice infestation was 55.4%. The findings indicated the need to develop appropriate intervention programmes both at school and community levels.

Flexural rigidity of marginal bands isolated from erythrocytes of the newt

The marginal band is a bundle of microtubules residing at the periphery of nucleated erythrocytes of nonmammalian vertebrates and some invertebrates. Marginal bands from erythrocytes of the newt (Notopthalmus viridescens) were isolated from the cells as intact structures by treatment with detergent and either mild protease or high salt. Isolated bands were subjected to mechanical testing by stretching the band between a glass microhook and a calibrated glass fiber. The deflection of the fiber provided a measure of the force on the band. The flexural rigidity of the band was determined from measurements of the band deformation as a function of applied force. Bands isolated with either of two proteases (pepsin or elastase) or with high salt exhibited elastic behavior with a flexural rigidity of approximately 9.0 X 10(-12) dyn.cm2. Treatment of bands with chymopapain caused an increase in band rigidity and inelastic behavior. Estimates of the contribution of the band to cellular rigidity are made based on the measurements of the structural properties of the isolated band. The band provides the cell with a large resistance to indentations at the rim and to large extensions, while maintaining a high degree of flexibility in small extensions or flexure.

Measurement of the extensional and flexural rigidities of a subcellular structure: marginal bands isolated from erythrocytes of the newt

The elastic properties of marginal band, a microtubular structure isolated from the newt (notophthalmus viridescens) have been measured. Bands were isolated using Triton X-100 and pepsin at pH 6.8 according to the method of Cohen (1978). Isolated bands were manipulated with a glass microhook in a buffer-filled chamber under the microscope. Single bands were stretched between the hook and a thin glass fiber. The fiber was calibrated so that the force on the band could be calculated from the displacement of the fiber. The data pairs of force versus band deflection were analyzed according to the theoretical work of Libai and Simmonds (1983) to obtain the flexural and extensional rigidities of the band. Band dimensions calculated from the data were consistent with microscopically determined values. The average flexural rigidity of the bands (EI) was 5.3 X 10(-13) dyn X cm2 and the average extensional rigidity (EA) was 0.017 dyn. Compared to the cell membrane, the marginal band is nearly inextensible and has a much greater resistance to bending, indicating that the band makes an important contribution to the deformability of the circulating cell.

An examination of students' attitudes toward the elderly

A study, employing Kogan's Old People Scale, was conducted to investigate undergraduate pharmacy students' attitudes toward the elderly. A total of 266 students from one school of pharmacy in their last three years of schooling comprised the sample. Demographic and experiential factors with the aged also were examined as to their relationship with the students' attitudes, but only one of these variables was found to be significant. Female students had a significantly more favorable attitude toward the aged than males. Overall the results showed that the students had a favorable attitude toward the elderly, which was consistent with other studies employing college students, but which was in contrast to other health professionals and medical and dentistry students. A discussion is made as to why this difference exists and the importance of future research in this area.