A case of purulent pneumococcal pericarditis

Background

Purulent bacterial pericarditis is a rare and potentially fatal disease. The course may be fulminant, and the presentation may pose a diagnostic challenge.

Biochemical, metabolic and morphological characteristics of human neutrophil activation with pepstatin A.

Pepstatin A, a chemotactic pentapeptide, elicited a concentration-dependent extracellular release of granule-associated beta-glucuronidase and lysozyme from, and generation of superoxide anion (O2-) by, cytochalasin B (CB)-treated human neutrophils. Prior exposure of neutrophils to pepstatin A before the addition of CB, suppressed, in a time-dependent fashion, the subsequent production of O2- and exocytotic response. The rate and amount of enzymes released and O2- generated by pepstatin A-activated neutrophils were significantly enhanced in the presence of extracellular calcium. Pepstatin A-elicited degranulation and O2- production were suppressed by the intracellular calcium antagonist, 8-(N,N-diethylamino)-octyl-(3, 4, 5-trimethoxy) benzoate hydrochloride (TMB-8). Granule exocytosis and O2- generation by pepstatin A-treated neutrophils were suppressed by the sulphydryl reagents, N-ethylmaleimide (NEM) and iodoacetic acid (IA), and by the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG). Sodium cyanide was inactive. Preincubation of neutrophils with pepstatin A "desensitized' the cells to a subsequent exposure to pepstatin A or the chemotactic tripeptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP). Pepstatin A-induced desensitization of granule enzyme release and O2- generation appears to be stimulus-specific in that phorbol myristate acetate (PMA) was capable of eliciting normal responses from pepstatin A-pretreated cells. The morphological changes observed in pepstatin A-treated neutrophils are reminiscent of those seen in cells exposed to FMLP.     

Contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium

Chitosan, a derivative of the bio-polysaccharide chitin, has shown promise as a bioactive material for implant, tissue engineering and drug-delivery applications. The aim of this study was to evaluate the contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium. Rough ground titanium (Ti) coupons were solution cast and bonded to 91.2% de-acetylated chitosan (1 wt% chitosan in 0.2% acetic acid) coatings via silane reactions. Non-coated Ti was used as controls. Samples were sterilized by ethylene oxide gas prior to experiments. Contact angles on all surfaces were measured using water. 5 x 10(4) cells/ml of ATCC CRL 1486 human embryonic palatal mesenchyme (HEPM) cells, an osteoblast precursor cell line, were used for the cell attachment study. SEM evaluations were performed on cells attached to all surfaces. Contact angles and cell attachment on all surfaces were statistically analyzed using ANOVA. The chitosan-coated surfaces (76.4 +/- 5.1 degrees) exhibited a significantly greater contact angle compared to control Ti surfaces (32.2 +/- 6.1 degrees). Similarly, chitosan-coated surfaces exhibited significantly greater (P < 0.001) albumin adsorption, fibronectin adsorption and cell attachment, as compared to the control Ti surfaces. Coating chitosan on Ti surfaces decreased the wettability of the Ti, but increased protein adsorption and cell attachment. Increased protein absorption and cell attachment on the chitosan-coated Ti may be of benefit in enhancing osseointegration of implant devices.     

Racial influence in renal stone disease: a Saskatchewan story

Data was obtained from two separate governement sources in an effort to review the prevalence of kidney stone disease in the province of Saskatchewan for the years 1983-1988 inclusive. The data revealed a statistally significant difference in prevalence rate among different ethnic groups within the population. Aboriginal people were found to have a prevalence rate approximately one-third that of the nonaboriginal (non-native) population. A renal stone episode prevalence of 0.858 per 1000 population compared to 0.222 per 1000 population in aboriginal people (p.<.001). The reasons for this difference could not be retrospectively associated with geographical variation. A discussion of other possible causes in association is offered, but it is felt that, in the end, more research into this area is required.     

National Scale Real-Time Surveillance of SARS-CoV-2 Variants Dynamics by Wastewater Monitoring in Israel

In this report, we describe a national-scale monitoring of the SARS-CoV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of 13 wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19/A20 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December 2020 and March 2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021 and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February–March 2021. This study demonstrates the importance of monitoring SC-2 variant by using a combination of inclusive and selective PCR tests on a national scale through wastewater sampling, which is far more amendable for high-throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1, BA.2) and other variants.     

Bilateral Refractive Changes in Vascularized Pigment Epithelial Detachment Treated by Anti-VEGF Therapy

We report the case of a patient bilaterally treated with anti-VEGF compounds for bilateral massive vascularized retinal pigment epithelial detachment (PED). During the years prior to treatment, PED growth was accompanied by gradual hypermetropization. After right intraocular injection of bevacizumab followed by three bilateral aflibercept injections, the PED flattened resulting in a rapid relative myopization. This case illustrates ocular refractive properties associated with PED and its response to treatment. This case also highlights the importance of assessing refraction in age-related macular degeneration patients experiencing substantial PED amplitude changes.Key Words: Bevacizumab, Aflibercept, Age-related macular degeneration, Acquired vitelliform lesions, Retinal pigment epithelial detachment, Refractive changes, Spectacles, Hypermetropization, Myopization     

Functional trait space and the latitudinal diversity gradient

The processes causing the latitudinal gradient in species richness remain elusive. Ecological theories for the origin of biodiversity gradients, such as competitive exclusion, neutral dynamics, and environmental filtering, make predictions for how functional diversity should vary at the alpha (within local assemblages), beta (among assemblages), and gamma (regional pool) scales. We test these predictions by quantifying hypervolumes constructed from functional traits representing major axes of plant strategy variation (specific leaf area, plant height, and seed mass) in tree assemblages spanning the temperate and tropical New World. Alpha-scale trait volume decreases with absolute latitude and is often lower than sampling expectation, consistent with environmental filtering theory. Beta-scale overlap decays with geographic distance fastest in the temperate zone, again consistent with environmental filtering theory. In contrast, gamma-scale trait space shows a hump-shaped relationship with absolute latitude, consistent with no theory. Furthermore, the overall temperate trait hypervolume was larger than the overall tropical hypervolume, indicating that the temperate zone permits a wider range of trait combinations or that niche packing is stronger in the tropical zone. Although there are limitations in the data, our analyses suggest that multiple processes have shaped trait diversity in trees, reflecting no consistent support for any one theory.Species richness increases toward the equator (1, 2) in major clades of both extant and extinct species of plants and animals (3, 4). The generality of the pattern hints at a correspondingly general explanation, yet the latitudinal gradient in species richness remains one of ecology’s greatest unsolved puzzles. Long-running debates over the causes of the latitudinal gradient of species richness have focused on ecological, evolutionary, and geographic explanations (5–10). Although there has been some progress (11), it is also increasingly clear that there are numerous obstacles to understanding the primary drivers of the latitudinal gradient, including an ever-increasing number of hypotheses (12, 13), challenges in clearly separating their interdependencies (14, 15), and difficulties in rigorously falsifying their assumptions and predictions (16).More powerful tests of biodiversity theories need to move beyond species richness and instead explicitly focus on the mechanisms generating the gradient, by recasting the theories in terms of other measures of diversity, such as functional diversity (17–19). For example, explanations that assume species richness is limited by resource availability have often focused on the strength of species interactions, life history differences, and environmental constraints on how species pack into niche space (20). Evolutionary hypotheses have focused on differences in diversification rates, as well as the influence of species interactions on diversification rates (9). These interaction-based explanations implicitly refer to the degree of ecological differentiation among species, and therefore to trait dispersion within clades and assemblages, suggesting that patterns of functional diversity may provide a more powerful test of theory than taxonomic richness (21).A particularly important concept that unifies many ecological and evolutionary theories is the concept of the Hutchinsonian multidimensional niche (22). Hutchinsonian niches can be quantified by assessing the functional trait hypervolumes that characterize phenotypic space occupied by a set of species. Quantifying the volume, overlap, and packing of functional trait space at different spatial scales enables inferences about how differing ecological and evolutionary processes structure functional diversity and ecological strategies (23, 24).Here, we recast several contrasting hypotheses for the latitudinal gradient in terms of functional trait space. We focus on the proximate ecological mechanisms that ultimately can influence evolutionary processes. We quantify tree functional trait space across latitude at three spatial scales: (i) within assemblages (alpha), (ii) among assemblages (beta), and (iii) among biomes (gamma). For alpha and beta analyses, we use tree species assemblage data from 620 standardized 0.1-ha forest plots (Fig. 1A); for gamma analyses, we calculated the latitudinal range distributions for 520 New World tree species where we had sufficient data on geographic distribution and functional traits. In total, across all analyses, we used paired geographic occurrence data with trait data for 6,839 tree species.Open in a separate windowFig. 1.(A) Spatial distribution of the 620 0.1-ha forest plots used in this study. Plots are colored by richness. Plots cover most of the New World forested climate space (Fig. S1). (B) Relationship between absolute latitude and alpha hypervolume for tropical (red triangles) and temperate (blue pluses) plots. (C) Alpha hypervolume as a function of effective species richness (number of species with full trait coverage). We compare this hypervolume with a null expectation based on sampling the same number of species from the regional pool (median, dark gray line; 90% quantile range, light gray envelope).We primarily measured hypervolumes for three central traits hypothesized to characterize major axes of ecological strategy variation (25): specific leaf area (SLA), maximum height, and seed mass. SLA represents the tradeoff between leaf longevity and maximum photosynthetic rate (26); height is important for light competition and dispersal (27); and seed mass represents tradeoffs between fecundity, dispersal, and seedling survival (27). Although whole-plant resource strategies can be more fully assessed in higher dimensions (28, 29), we focus on these traits because of data availability (Materials and Methods). We use a hypervolume algorithm for calculating the volume and overlap of trait space (30) (Materials and Methods). All hypervolumes are reported in units of SDs of centered and scaled log-transformed trait values, raised to the power of the number of trait dimensions used.At all scales, our overall results and conclusions are similar (i) with and without gap-filling missing data, (ii) if we use convex hulls instead of hypervolumes to calculate trait spaces, and (iii) if we include additional trait axes. Additional details are given in Figs. S2–S7.