Brightfield and fluorescence in-channel staining of thin blood smears generated in a pumpless microfluidic.

Effective staining of peripheral blood smears by increasing contrast of intracellular components and biomarkers is essential for the accurate characterization, diagnosis, and monitoring of various diseases such as malaria. To assess the potential for automation of stained whole human blood smears at the point-of-care (POC), brightfield and fluorescence staining protocols were adapted for smears generated in channels of pumpless microchannels and compared to a standard glass smear. A 3× concentration Giemsa brightfield staining solutions (10, 33, and 50% dilution), and Acridine Orange fluorescence staining solutions (12 µg mL-1) were evaluated with human blood smears containing malaria parasites within a microfluidic channel. Giemsa staining at 33% dilution showed an optimal combination of contrast and preservation of cellular morphology, while 50% dilutions showed significant cellular crenation and 10% dilutions did not show desired contrast in brightfield imaging. Fluorescence staining at 12 µg mL-1 using Acridine Orange showed clear separability between the fluorescent intensities of the malaria parasites and that of the red blood cells (RBCs) and background. However, compared to glass smears, these exhibited reduced signal intensity as well as inverted contrast of RBCs and background. These results demonstrate that peripheral thin blood smears generated in pumpless microfluidic can be successfully stained in-channel with a simple, one-step procedure to permit brightfield and fluorescence imaging.

Influence of anxiolytic premedication on vasovagal reactions and home readiness following outpatient intrathecal anaesthesia-A retrospective analysis.

BACKGROUND: Vasovagal reactions during application of intrathecal anaesthesia (IA) are associated with high anxiety levels. A high percentage of patients undergoing outpatient surgery suffer from anxiety. Anxiolytic premedication in day-surgery is suspected to delay recovery and discharge and is, therefore, not routinely used. The aim of this retrospective analysis was to detect the influence of anxiolytic premedication on the incidence of vasovagal reactions and time until discharge home. METHODS: Anaesthesia records of all patients undergoing outpatient surgery under low-dose IA from January 2008 to June 2017 were analysed. Incidences of vasovagal reactions with a decrease in blood pressure and/or heart rate and need for cardiovascular activating medications were documented. Patients were categorised as having received an anxiolytic premedication or not. The time from intrathecal injection of the local anaesthetic until readiness for discharge was recorded. RESULTS: The records of 2747 patients were analysed. One thousand two hundred and ninety-one of them received an anxiolytic premedication of 1-2 mg midazolam intravenously. Three hundred and fourteen patients had vasovagal incidents during application of IA (no premedication n = 217 [15.0%], premedication n = 97 [7.5%], P < 0.0001). Premedication did not prolong time to achieve readiness for discharge (mepivacaine: P = 0.5886, chloroprocaine: P = 0.1555). However, in the prilocaine group, premedication led to a significantly earlier achievement of readiness for discharge (P = 0.0002). CONCLUSION: Anxiolytic premedication significantly reduces the incidence of vasovagal reactions during the application of IA and does not affect time until readiness for discharge.

Retrospective analysis of mepivacaine, prilocaine and chloroprocaine for low-dose spinal anaesthesia in outpatient perianal procedures.

PURPOSE: Perianal procedures are carried out in an outpatient setting regularly. The purpose of this retrospective analysis was to investigate the impact of different local anaesthetics (LA) for spinal anaesthesia (SPA) on operating room (OR) efficiency (perioperative process times, turnaround times) and postoperative recovery. This study aims on the determination of the optimal LA for low-dose SPA in the specific setting of a high-volume day-surgery centre. METHODS: Anaesthesia records of all patients undergoing perianal outpatient surgery under saddle-block SPA at the Mannheim University Medical Centre from 2008 until 2017 were analysed. Patients were categorized as having received prilocaine, mepivacaine or chloroprocaine. RESULTS: Two thousand seven hundred forty-six patients were included. Postoperative recovery was faster for chloroprocaine 1% compared with both other LAs. Preoperative processes but not process times in the OR were shorter for chloroprocaine. In contrary, turnaround times were significantly prolonged when chloroprocaine had been used, leading to reduction of OR efficiency. CONCLUSION: Low-dose SPA provides reliable blocks for perianal surgery. Considerations on the choice of LA for SPA must include not only the recovery profile, but also the impact on OR efficiency. Due to shorter turnaround times and a manageable prolonged duration of stay, prilocaine is the preferable LA for low-dose SPA in perianal outpatient surgery at a high-volume day-surgery centre.

Hydrostatic pressure activates ATP-sensitive K+ channels in lung epithelium by ATP release through pannexin and connexin hemichannels.

Lungs of air-breathing vertebrates are constantly exposed to mechanical forces and therefore are suitable for investigation of mechanotransduction processes in nonexcitable cells and tissues. Freshly dissected Xenopus laevis lungs were used for transepithelial short-circuit current (ISC) recordings and were exposed to increased hydrostatic pressure (HP; 5 cm fluid column, modified Ussing chamber). I(SC) values obtained under HP (I(5cm)) were normalized to values before HP (I(0cm)) application (I(5cm)/I(0cm)). Under control conditions, HP decreased I(SC) (I(5cm)/I(0cm)=0.84; n=68; P<0.0001). This effect was reversible and repeatable ≥30 times. Preincubation with ATP-sensitive K(+) channel (K(ATP)) inhibitors (HMR1098 and glibenclamide) prevented the decrease in I(SC) (I(5cm)/I(0cm): HMR1098=1.19, P<0.0001; glibenclamide=1.11, P<0.0001). Similar effects were observed with hemichannel inhibitors (I(5cm)/I(0cm): meclofenamic acid=1.09, P<0.0001; probenecid=1.0, P<0.0001). The HP effect was accompanied by release of ATP (P<0.05), determined by luciferin-luciferase luminescence in perfusion solution from the luminal side of an Ussing chamber. ATP release was abrogated by both meclofenamic acid and probenecid. RT-PCR experiments revealed the expression of pannexin and connexin hemichannels and KATP subunit transcripts in X. laevis lung. These data show an activation of KATP in pulmonary epithelial cells in response to HP that is induced by ATP release through mechanosensitive pannexin and connexin hemichannels. These findings represent a novel mechanism of mechanotransduction in nonexcitable cells.