Role of Vocal Cord Function and Dysfunction in Patients Presenting with Symptoms of Acute Asthma Exacerbation

A total of 48 patients presenting to the emergency department as acute asthma exacerbation were prospectively studied. Rhinolaryngoscopy was conducted with simultaneous flow measurements and spirometry performed before and after the procedure. Measurements of the vocal cord opening during various phases of respiration were analyzed. Only 4 of 48 patients had anterior two-thirds closure of the vocal cords with a diamond-shaped opening posteriorly during expiration. One additional patient had inspiratory and expiratory closure of the vocal cords. The previously unreported high incidence of anterior two-thirds closure (10.4%) of the vocal cords suggests that the upper airway has a role to play in a significant number of patients presenting with symptoms of asthma exacerbation.     

Folding and ligand recognition of the TPP riboswitch aptamer at single-molecule resolution

Thiamine pyrophosphate (TPP)-sensitive mRNA domains are the most prevalent riboswitches known. Despite intensive investigation, the complex ligand recognition and concomitant folding processes in the TPP riboswitch that culminate in the regulation of gene expression remain elusive. Here, we used single-molecule fluorescence resonance energy transfer imaging to probe the folding landscape of the TPP aptamer domain in the absence and presence of magnesium and TPP. To do so, distinct labeling patterns were used to sense the dynamics of the switch helix (P1) and the two sensor arms (P2/P3 and P4/P5) of the aptamer domain. The latter structural elements make interdomain tertiary contacts (L5/P3) that span a region immediately adjacent to the ligand-binding site. In each instance, conformational dynamics of the TPP riboswitch were influenced by ligand binding. The P1 switch helix, formed by the 5′ and 3′ ends of the aptamer domain, adopts a predominantly folded structure in the presence of Mg²⁺ alone. However, even at saturating concentrations of Mg²⁺ and TPP, the P1 helix, as well as distal regions surrounding the TPP-binding site, exhibit an unexpected degree of residual dynamics and disperse kinetic behaviors. Such plasticity results in a persistent exchange of the P3/P5 forearms between open and closed configurations that is likely to facilitate entry and exit of the TPP ligand. Correspondingly, we posit that such features of the TPP aptamer domain contribute directly to the mechanism of riboswitch-mediated translational regulation.     

Injuries after Use of the Lacrimatory Agent Chloroacetophenone in a Confined Space

When the lacrimatory agent chloroacetophenone was released into 44 prisoner cells, 8 prisoners required hospitalization and 20 more received outpatient physician care for injuries. Contact with water contributed to the injuries caused by chloroacetophenone, but prolonged exposure in a confined space was probably the principal cause of morbidity. In a confined space the lacrimatory agent chloroacetophenone is relatively toxic.     

Measurement of salivary cortisol – effects of replacing polyester with cotton and switching antibody

Stable performance between‐runs are essential in longitudinal studies and when different studies are being compared. However, changes in analytical kits and laboratory material occur and have the potential to threaten analytical stability. In the present case, we examined how salivary cortisol measurements in our laboratory were affected by: 1) changes in the tampon material and 2) changes in the antibody of the analytical kit. In study 1, saliva from healthy subjects (n = 19) was split and spiked to Salivette^® polyester and cotton tampons, respectively, and treated as ordinary samples before being analysed for cortisol using a Spectria RIA kit for cortisol. In study 2, 68 anonymous saliva samples were analysed with the Spectria Cortisol RIA kit both before and after the manufacturer changed the antibody. The change from polyester to cotton tampons reduced the measured concentration of salivary cortisol by 62?%. A difference of 12?% between the two runs with different antibodies could not be attributed to differences in storage or in thawing and freezing of samples. To conclude, both a change in the material of the Salivette used for collecting saliva samples as well as a change of antibody in a kit can have a major impact on measurements, as illustrated here for concentrations of cortisol in saliva. It is therefore recommended always to check that the analysis stays in statistical control in one's own laboratory when changes are made, even if the manufacturer reports that the changes should have no effects.