A shock to the (health) system: experiences of adults with rare disorders during the first COVID-19 wave.

Background: Before COVID-19, people with rare diseases (RD) experienced numerous disparities in quality of life and healthcare access and quality, yet little is known about the experiences of this underserved group during the pandemic.

Results: During the first wave of the COVID-19 pandemic in the United States, spring and summer of 2020, 759 participants representing 231 unique RDs responded to open-ended questions about the impact of the pandemic on life with a RD, healthcare access, and coping. Qualitative conventional content analysis was used to analyze responses.

Monte Carlo modeling of angiographic optical coherence tomography.

Optical coherence tomography (OCT) provides both structural and angiographic imaging modes. Because of its unique capabilities, OCT-based angiography has been increasingly adopted into small animal and human subject imaging. To support the development of the signal and image processing algorithms on which OCT-based angiography depends, we describe here a Monte Carlo-based model of the imaging approach.

A resistive mesh phantom for assessing the performance of EIT systems.

Assessing the performance of electrical impedance tomography (EIT) systems usually requires a phantom for validation, calibration, or comparison purposes. This paper describes a resistive mesh phantom to assess the performance of EIT systems while taking into account cabling stray effects similar to in vivo conditions. This phantom is built with 340 precision resistors on a printed circuit board representing a 2-D circular homogeneous medium.

A 3-D hybrid finite element model to characterize the electrical behavior of cutaneous tissues.

Finite element modeling of the skin is useful to study the electrical properties of cutaneous tissues and gain a better understanding of the current distribution within the skin. Such an epithelial finite element model comprises extremely thin structures like cellular membranes, nuclear membranes, and the extracellular fluid. Meshing such narrow spaces considerably increases the number of elements leading to longer computing time.

A multi-frequency EIT system design based on telecommunication signal processors.

A multi-frequency electrical impedance tomography system for cardiopulmonary monitoring has been designed with specialized digital signal processors developed primarily for the telecommunications sector. The system consists of two modules: a scan-head and a base-station. The scan-head, located close to the patient's torso, contains front-end circuits for measuring transfer impedance with a 16-electrode array.

Real-time management of faulty electrodes in electrical impedance tomography.

Completely or partially disconnected electrodes are a fairly common occurrence in many electrical impedance tomography (EIT) clinical applications. Several factors can contribute to electrode disconnection: patient movement, perspiration, manipulations by clinical staff, and defective electrode leads or electronics. By corrupting several measurements, faulty electrodes introduce significant image artifacts.

Impact of Toll-like receptor signalling on urinary tract infection.

Toll-like receptors (TLRs), components of the innate immune system, play a pivotal role in the pathogenesis of urinary tract infection (UTI). TLRs (especially TLR4) expressed both by epithelial and non-epithelial cells, e.g.

Accounting for hardware imperfections in EIT image reconstruction algorithms.

Electrical impedance tomography (EIT) is a non-invasive technique for imaging the conductivity distribution of a body section. Different types of EIT images can be reconstructed: absolute, time difference and frequency difference. Reconstruction algorithms are sensitive to many errors which translate into image artefacts.

A method for modelling and optimizing an electrical impedance tomography system.

Electrical impedance tomography (EIT) image reconstruction is an ill-posed problem requiring maximum measurement precision. Recent EIT systems claim 60 to 80 dB precision. Achieving higher values is hard in practice since measurements must be performed at relatively high frequency, on a living subject, while using components whose tolerance is usually higher than 0.

1-alpha-calcidol modulates major human monocyte antigens and toll-like receptors TLR 2 and TLR4 in vitro.

Since vitamin D derivatives are known to interfere with the cellular immune response, we analysed the possible effect of 1-alpha-calcidol (AC) on major monocyte antigens CD14 (an endotoxin receptor), HLA-DR, and toll-like recptors 2 and 4 (TLR2, TLR4). Peripheral blood monocytes were isolated from healthy donors and cultured by standard protocol followed by incubation with various concentrations of AC in unstimulated and LPS-activated cells. After 24, 48 and 72 hours cells were harvested and analysed for the expression of antigens by flowcytometry.

On the role of item similarity in retrieval-induced forgetting.

We report on two experiments designed to examine how the similarity of retrieval-practised and not-retrieval-practised items influences the amount of retrieval-induced forgetting. Participants studied categorised item lists with each category consisting of exemplars from two different semantic subcategories. Using both the retrieval practice paradigm (Experiment 1) and the output interference paradigm (Experiment 2) we found that the retrieval of a subset of the studied items impaired the subsequent recall of the nonpractised items if the two types of items were fairly dissimilar to each other (same category but different subcategory) but did not induce impairment if the two types of items were highly similar (same category and subcategory).

[Cultivated keratinocytes on micro-carriers: in vitro studies of a new carrier system].

Epidermal grafts from confluently cultivated keratinocytes have been used since the early eighties for the treatment of severe burns, where the shortage of donor sites for split-thickness skin grafts did not allow for adequate wound coverage. The difficult handling of these grafts as well as the advanced differentiation of their epithelial cells into a multilayer sheet poses a problem for their clinical application. The aim of the study was to characterize cultivated keratinocytes, as well as to observe their migration and proliferation from the MC onto a surface.

Time-resolved infrared ATR measurements of liposome transport kinetics in human keratinocyte cultures and skin reveals a dependence on liposome size and phase state.

A novel in vitro method for studying the permeation kinetics of superficially applied liposomes or vesicles through layers of human skin or keratinocytes on a solid support is presented, employing attenuated total reflection infrared spectroscopy. The method is applied to investigate transport kinetics of unilamellar vesicles of dimyristoylphosphatidylcholine (DMPC) through cultured human keratinocyte layers and through human skin. We find a strong resemblance of the qualitative features of the permeation kinetics of small unilamellar DMPC vesicles for skin and keratinocytes.

[Use of keratinocyte cultures in treatment of severe burns--experiences up to now, outlook for further subsequent developments].

There is a world-wide growing interest in cultured epithelium. It is commonly accepted that cultured epithelial auto- or allografts can stimulate wound healing and shorten re-epithelialization time. Sheets of cultured autologous epidermal cells have been used for more than 15 years as grafts to achieve permanent coverage of full-thickness burn wounds.

[Keratinocyte culture and transplantation in burns].

The culture and transplantation of keratinocytes are considered an important progress in the treatment of severe burns. The keratinocyte grafts take best (50 to 90%) on remaining dermal structures after deep dermal (II b) burns. Since 1988 we culture also donor keratinocytes.

Phospholipase A activity in Pseudomonas aeruginosa.

Our study describes the production, purification and properties of an enzyme from Pseudomonas aeruginosa displaying the properties of phospholipase A. Maximal amounts of enzyme could be detected in the culture supernatant when the bacterium was grown for 3 to 5 days at 37 degrees C in stirred flask cultures containing brain heart infusion. The enzyme was purified by polyethylenimine precipitation and ammonium sulfate precipitation followed by gel filtration.

Composite grafts of autogenic cultured epidermis and glycerol-preserved allogeneic dermis for definitive coverage of full thickness burn wounds: case reports.

In patients with extensive deep burns and scarce donor sites autogenic cultured epithelial grafts (auto-CEG) have become a real alternative. In deep burns the 'take' rate of auto-CEG applied directly on subcutaneous fat, fascia or muscle is unreliable and frequently disappointing. The auto-CEG seems to need a dermal base.

Discrimination of the irritancy potential of surfactants in vitro by two cytotoxicity assays using normal human keratinocytes, HaCaT cells and 3T3 mouse fibroblasts: correlation with in vivo data from a soap chamber assay.

Cell cultures have been proposed as a promising model for local tolerance testing. This study evaluated the cytotoxic effects of surfactants on early passage normal human keratinocytes, transformed human keratinocytes (HaCaT cells) and Swiss 3T3 embryonic mouse fibroblasts. Cell membrane integrity, as assessed by the release of the vital dye neutral red, and cell proliferation, as assessed by measurement of the total protein content, were both affected in a dose-dependent manner in response to surfactant exposure.

MTT-assay and neutral red release (NRR)-assay: relative role in the prediction of the irritancy potential of surfactants.

A comparative study on the in vitro and in vivo irritancy of anionic, amphoteric and non-ionic surfactants was performed. In vitro ED50 values of the surfactants were determined by two cytotoxicity assays, the dimethylthiazoldiphenyltetrazoliumbromide (MTT) assay and the neutral red release (NRR) assay on serum-free cultured human foreskin keratinocytes. In vivo human irritancy data were obtained by a 24 hour occlusive patch test in volunteers and the irritant skin response quantified by visual scoring, evaporimetry and colorimetry.

Evidence for the phagocytosis of intact oligolamellar liposomes by human keratinocytes in vitro and consecutive intracellular disintegration.

While there is evidence for the use of liposomes as drug carriers upon topical application to the skin, the underlying mechanisms are far from being clear. Therefore human keratinocytes grown in vitro were exposed to large oligolamellar liposomes. After attachment and invagination these particles can be found unchanged within the cytoplasm both inside and outside of lysosomes.

[Skin culture--keratinocytes].

Our efforts to cultivate keratinocytes and to use cultivated epidermal grafts which are then transplanted onto deep second- and third-degree burns and donor sites date back in 1987. Our laboratory is now able to provide our intensive care unit with cultured epidermografts as a routine procedure. Furthermore, we have developed a simple method for cryopreservation of cultured human epidermal keratinocytes.

Absence of extracellular enzyme activity and cytotoxicity in cell-free culture filtrates of Haemophilus ducreyi.

Ten isolates of Haemophilus ducreyi, including seven clinical isolates and three laboratory reference strains, were assessed for their ability to produce extracellular enzymes which might contribute to their pathogenicity. Protease, elastase, lecithinase, lipase or collagenase enzyme activity were not detected in culture filtrates from any of the isolates tested using either plate or spectrophotometrical assays. Furthermore, cell-free culture filtrates did not exhibit cytotoxic activity in vitro when tested using either an established tissue culture cell line (Vero) or a primary cell culture of human keratinocytes.

Skin banking: a simple method for cryopreservation of split-thickness skin and cultured human epidermal keratinocytes.

A simple unit has been developed for the simultaneous passive cooling of small and large amounts of allograft or autograft split-thickness skin, as well as cultured human epidermis. An expanded polystyrene box of variable size, aluminum plates, and cellulose tissue are fused. This unit is cooled in a -70 degrees C constant-temperature mechanical refrigerator.

[Minimum inhibitory concentration and minimum bactericidal concentration of tetracycline and erythromycin in 35 recent Munich isolates of Chlamydia trachomatis].

Thirty-five recent clinical isolates of Chlamydia trachomatis were subcultured and subjected to antimicrobial susceptibility testing with tetracycline and erythromycin. Detection of typical chlamydial inclusion bodies and elementary bodies was based on the use of fluorescence-labelled monoclonal antibodies. Minimum inhibitory concentration being defined as the lowest concentration suppressing all inclusion body formation and minimum bactericidal concentration as the lowest concentration preventing all detectable chlamydial growth, both these parameters were studied.