Chembio DPP COVID-19 IgM/IgG Serological Testing: Laboratory Validation, Guidelines, and Recommendations.

BACKGROUND: On January 30, 2020, WHO declared COVID-19 a pandemic. In this article we describe our experience at Richmond University Medical Center with Chembio serological IgM, IgG testing. METHODS: In this prospective cohort study of patients and hospital employees, we utilized Chembio COVID-19 IgM/IgG serological testing in addition to Cepheid RT-PCR analysis. RESULTS: We evaluated the performance of Chembio serological test for IgM and IgG as an employee screening tool in a community hospital setting. The total number of currently asymptomatic employees screened was 1,866 from the Richmond University Medical Center. The non-exposed group included 1,253 (67.1%) employees with no significant clinical history and non-reactive IgM and IgG antibodies. The convalescent group included 255 (13.7%) of the employees with elevation of IgG only, 18 (1%) employees with past history of positive PCR and COVID-19 who currently have non-reactive IgM and IgG antibodies or demonstrate elevated IgG only, followed by 3 employees (< 1%) with no past clinical history who demonstrated reactive IgM and IgG antibodies and negative follow up by PCR. The reported 14.9% exposure/convalescent rate is lower than the reported 20% by the Department of Health and Governor Andrew Cuomo and may represent a better utilization of personal protective equipment, better hand washing techniques, and better disinfection procedures combined with strict social distancing. CONCLUSIONS: Chembio's performance is satisfactory; however, hospitals must design their own policies addressing: who needs to be screened and who will interpret the results as well as constructing management algorithms for employees with no previous history and current double positive antibodies.

In vitro evaluation and in vivo demonstration of a biomimetic, hemocompatible, microfluidic artificial lung.

Despite the promising potential of microfluidic artificial lungs, current designs suffer from short functional lifetimes due to surface chemistry and blood flow patterns that act to reduce hemocompatibility. Here, we present the first microfluidic artificial lung featuring a hemocompatible surface coating and a biomimetic blood path. The polyethylene-glycol (PEG) coated microfluidic lung exhibited a significantly improved in vitro lifetime compared to uncoated controls as well as consistent and significantly improved gas exchange over the entire testing period. Enabled by our hemocompatible PEG coating, we additionally describe the first extended (3 h) in vivo demonstration of a microfluidic artificial lung.

Comparison of the durability of cadaveric and autologous fascia using an in vivo model.

OBJECTIVES: To assess the durability of both autologous and cadaveric fascia using an animal model. The pubovaginal sling procedure can be performed using autologous, cadaveric, or synthetic materials. Few data are available about the strength and durability of these materials. METHODS: Rectus abdominus fascia harvested from 6 female Sprague-Dawley rats was processed by Tutogen Medical. In 20 female Sprague-Dawley rats, three different types of fascia were implanted subcutaneously into each animal: autologous rectus abdominus fascia harvested at the time of surgery; rat cadaveric fascia processed by Tutogen; and human cadaveric fascia (Tutogen). The rats were killed at 2 months (10 rats) and 4 months (10 rats) after implantation. The mechanical properties of the tissue were assessed using the trouser tear test, and the fracture toughness was calculated. RESULTS: Compared with the fracture toughness before implantation, the implanted rat autologous fascia decreased in toughness from 1763 to 1243 J/m(2) (P = 0.12), the implanted rat cadaveric fascia decreased in toughness from 1539 to 1022 J/m(2) (P = 0.02), and the implanted human cadaveric fascia decreased in toughness from 2120 to 1145 J/m(2) (P = 0.09). The fracture toughness of the implanted rat cadaveric fascia and rat autologous fascia did not differ significantly (P = 0.29). CONCLUSIONS: The changes in strength or elasticity can be detected using the trouser tear test to calculate the fracture toughness. Both cadaveric and autologous fascial grafts may decrease in toughness with time. The long-term durability of the graft may only be a minor factor in determining the success of the pubovaginal sling procedure.

An in vivo Comparative Study of Intersegmental Flexibility in the Ophiuroid Arm.

We present the first in vivo measurements of intersegmental rotation in the ophiuroid arm, comparing lateral bending performance in seven epifaunal species from Discovery Bay, Jamaica. The species studied include suspension-feeders, deposit-feeders, and scavengers, and also represent two major types of vertebral ossicle morphology. Animals were photographed with strobe illumination, and the angular deflections between arm segments were recorded. Despite considerable variation in vertebral morphology, ecology, and behavior, Discovery Bay ophiuroids show similar, overlapping distributions of maximal intersegmental rotations. Although interspecific differences in mean lateral flexibility can be statistically significant, absolute differences among species are small and of unknown functional significance. These quantitative data challenge long-standing assumptions about how the ophiuroid vertebral skeleton affects intersegmental flexibility, and how intersegmental flexibility per se affects an ophiuroid's ecological style or success.

The 1996 Lindberg Award. Calcium antagonists alter cell shape and induce procollagenase synthesis in keloid and normal human dermal fibroblasts.

Fibroblast cytomorphology is tightly coupled to phenotypic expression, particularly as it relates to extracellular matrix protein synthesis and degradation. We have observed that calcium antagonists, such as verapamil and trifluoperazine, depolymerize actin filaments and alter fibroblast cell shape from bipolar to spherical. Characteristically, the depolymerization of actin filaments, which mediates the cell shape change, turns on procollagenase gene expression in normal human skin fibroblasts. We have found the same effects of calcium antagonists on cell shape, cytoskeletal components, and induction of procollagenase in the keloid fibroblasts of three cell lines, CB792, CW792, and WT949. Rounded cells were seen in 74.8% of verapamil-treated and 86.7% of trifluoperazine-treated cells, whereas only 1.1% of the control cells were spherical. The percentage of cells that synthesized collagenase in the control, verapamil-treated, and trifluoperazine-treated groups was 3.8%, 42.8%, and 53.4%, respectively. Approximately 60% of rounded cells exhibited increased collagenase synthesis when the cells were treated with a calcium antagonist. These results indicate considerable heterogeneity in the phenotypic response to morphologic change. The amount of procollagenase synthesized in a cell was estimated by the fluorescence intensity of the fluorescein-labeled antibody. The normalized fluorescence intensity of procollagenase in the control cells was about 2 to 2.6 times that of background. In contrast, the normalized fluorescence intensity of procollagenase in the calcium antagonist-treated cells was about 2.4 to 12 times that of background. This high intensity level indicates an increase in procollagenase production in the calcium antagonist-treated cells. Calcium green dye used to study cytosolic calcium revealed that after cells were treated with verapamil, the cytosolic calcium ion concentration first increased and then decreased. The change of cytosolic calcium ion concentration may be related to the depolymerization of actin filaments and the alteration of cell shape.

Quantitative Branching Geometry of the Vascular System of the Blue Crab, Callinectes sapidus (Arthropoda, Crustacea): A Test of Murray's Law in an Open Circulatory System.

Murray's law predicts that there will be a radius-cubed relationship between the parent and daughter vessels of a branching system of vessels that carry the flow of a fluid, a relationship that theoretically minimizes the costs of building, maintaining, and operating the system. The vascular system of the blue crab, Callinectes sapidus, was replicated by corrosion casting at physiological pressures; vessel diameters were measured off the casts and used to calculate a junction exponent for each branch point. This study is the first quantitative description of the vascular branching geometry in an open circulatory system. The mean value derived from the arctan-transformed junction exponent distribution, 3.020, was not significantly different from the value of 3 predicted by Murray's law. The phylogenetic distance of arthropods from the animals previously studied in this context, sponges and mammals, is evidence for three independent evolutions of this branching relationship in biological fluid transport systems.

Effects of constant mechanical tension on the healing of rabbit flexor tendons.

The biomechanical effects of constant mechanical load on tendon repair in vitro were determined for rabbit flexor tendons. Tendons were removed from Zone II, transected, reapproximated with four simple sutures, and cultured in standard medium. Tendons from the right forelimbs were loaded with 3.1-g weights; tendons from the contralateral forelimbs served as unloaded tendons. Tenorrhaphies were disrupted at zero, one, three, and six weeks postsuturing by fixed-speed tensiometry. True maximum stress (strength), normalized energy absorbed, and tangent modulus steadily increased over time, becoming significantly greater than unincubated controls in the loaded and unloaded groups at six weeks. True strain at maximum stress increased with duration for unloaded tendons; after six weeks it was significantly greater than unincubated control tendons. This study demonstrates a method for quantifying the biomechanics of tendon after intrinsic tendon segment healing and presents the first biomechanical evaluation of constant tension applied across the laceration site during an in vitro healing phase.

Endogenous versus toxin-induced diabetes in rats: a mechanical comparison of two skin wound-healing models.

This study was designed to compare skin wound healing in three groups of Wistar rats: normal, genetically diabetic, and streptozotocin-induced diabetic. All diabetic animals received daily insulin. Full-thickness midline dorsal skin wounds were analyzed biomechanically for strength, toughness, and elasticity (Young's modulus) at 1 and 3 weeks after wounding. Wounds from normal controls were the strongest, toughest, and least compliant. Genetically diabetic rat wounds were the weakest and had the lowest elastic modulus. Wounds from the streptozotocin-induced rats were intermediate for all parameters measured (ANOVA, p = 0.001). Toxin-induced diabetes is less detrimental to skin wound healing than diabetes of endogenous origin. Whether this is due to basic differences in the models or to differences in duration of diabetes is unknown.

Renal sarcoidosis coexisting with hypernephroma.

Hypernephroma arising in a kidney infiltrated by sarcoidosis is unusual. To date, there has been no such case reported. The hypernephroma was suspected by the presence of localized parenchymal calcifications and confirmed by selective renal angiography.

Modes of Feeding in Aggregations of Barnacles and the Shape of Aggregations.

The interactions between the form of a barnacle aggregation, its flow environment, and the feeding behavior of each individual was determined in unidirectional flows; both models of barnacle aggregations and live barnacles were used. Hill-shaped aggregations of model barnacles captured significantly more particles than flat aggregations. In general, rows upstream of, and at the peak of, all hill-shaped profiles captured significantly more particles than downstream rows. Living barnacles located at, or upstream of, the peak of natural clusters captured significantly more food particles than did barnacles located downstream. Living barnacles located at, or upstream of, the highest point in a natural cluster fed passively, whereas barnacles downstream of the peak actively swept their cirral net against the flow. Flow was laminar up to the highest point in natural clusters, whereas flow was both reduced and turbulent over the downstream portions. Individual barnacles within a cluster differ in their feeding rates and net energy gains, and therefore differ in their growth such that, in unidirectional flow, the peak of a cluster will shift upstream over time; in oscillating flows, the clusters will develop a symmetrical profile.

Principles of design of fluid transport systems in zoology.

Fluid transport systems mediate the transfer of materials both within an organism and between an organism and its environment. The architecture of fluid transport systems is determined by the small distances over which transfer processes are effective and by hydrodynamic and energetic constraints. All fluid transport systems within organisms exhibit one of two geometries, a simple tube interrupted by a planar transfer region or a branched network of vessels linking widely distributed transfer regions; each is determined by different morphogenetic processes. By exploiting the signal inherent in local shear stress on the vessel walls, animals have repeatedly evolved a complex branching hierarchy of vessels approximating a globally optimal system that minimizes the costs of the construction and maintenance of the fluid transport system.

Particle capture by a pacific brittle star: experimental test of the aerosol suspension feeding model.

Ophiopholis aculeata, a suspension feeding brittle star, is capable of removing artificial particles from seawater by some mechanism or mechanisms other than sieving; the animal can capture a finite proportion of particles in all size classes available from at least 30 to 360 micrometers in diameter. A marked shift in the size distribution of particles caught by the animal toward larger particle sizes agrees with predictions derived from aerosol filtration theory. Adhesion of particles to the tube feet is strongly dependent on the presence of fixed charged groups on the surface of the particles.