Changes in ventilation distribution during general anesthesia measured with EIT in mechanically ventilated small children.

BACKGROUND: Atelectasis during general anesthesia is a risk for perioperative complications. EIT measurements were performed in mechanically ventilated healthy children during elective surgery to demonstrate the changes in ventilation distribution during general anesthesia. The ventilation distribution was quantified by calculating the Global Inhomogeneity index (GI). METHODS: EIT measurements were performed in 23 children (9 weeks-10 years) without lung disease to detect changes in regional ventilation during elective surgery. Three previously defined time points were marked during the measurement: after intubation and start of pressure-controlled ventilation (PCV), change to pressure support ventilation (PSV), and after extubation (spontaneous breathing-SB). Ventilation distribution based on regions of interest (ROI) and changes in end-expiratory volume (∆EELV) were collected at these time points and compared. The Global Inhomogeneity index was calculated at the beginning of pressure-controlled ventilation (PCV). RESULTS: With increasing spontaneous breathing, dorsal recruitment of atelectasis occurred. The dorsal ventilation fraction increased over the time of general anesthesia with increasing spontaneous breathing, whereas the ventral fraction decreased relatively (Difference ± 5.5 percentage points respectively; 95% CI; 3.5-7.4; p < 0.001). With the onset of spontaneous breathing, there was a significant reduction in end-expiratory volume (Difference: 105 ml; 95% CI, 75-135; p < 0.001). The GI of the lung-healthy ventilated children is 47% (SD ± 4%). CONCLUSION: Controlled ventilation of healthy children resulted in increased ventilation of the ventral and collapse of the dorsal lung areas. Restart of spontaneous breathing after cessation of surgery resulted in an increase in ventilation in the dorsal with decrease in the ventral lung areas. By calculating the GI, representing the ratio of more to less ventilated lung areas, revealed the presumed homogeneous distribution of ventilation. TRIAL REGISTRATION: ClinicalTrials.gov Registration ID: NCT04873999. First registration: 05/05/2021.

Antiparasitic activities of new lawsone Mannich bases.

A series of new lawsone Mannich bases derived from salicylaldehydes or nitrofurfural were prepared and tested for their activities against Leishmania major, Toxoplasma gondii, and Trypanosoma brucei brucei parasites. The hydrochloride salts 5a and 6a of the Mannich bases 2a and 3a, derived from unsubstituted salicylaldehyde and long-chained alkyl amines, were selectively and strongly active against T. gondii cells and appear to be new promising drug candidates against this parasite. Compound 6a showed an even higher activity against T. gondii than the known lawsone Mannich base 1b. Compound 4a, derived from salicylaldehyde and 2-methylaminopyridine, was also distinctly active against T. gondii cells. The derivatives 3a (salicyl derivative), 3b (3,5-dichloro-2-hydroxyphenyl derivative), and 3d (5-nitrofuranyl derivative) as well as the hydrochlorides 6a and 6b were also efficacious against T. b. brucei cells with compounds 3a and 3b being more selective for T. b. brucei over Vero cells when compared with the known control compound 1b. The derivatives 5a, 5c, 6a, and 6c proved to be up to five times more active than 1b against L. major promastigotes and up to four times more efficacious against L. major amastigotes.

Anti-trypanosomal activity of cationic N-heterocyclic carbene gold(I) complexes.

Two gold(I) N-heterocyclic carbene complexes 1a and 1b were tested for their anti-trypanosomal activity against Trypanosoma brucei parasites. Both gold compounds exhibited excellent anti-trypanosomal activity (IC50=0.9-3.0nM). The effects of the gold complexes 1a and 1b on the T. b. brucei cytoskeleton were evaluated. Rapid detachment of the flagellum from the cell body occurred after treatment with the gold complexes. In addition, a quick and complete degeneration of the parasitic cytoskeleton was induced by the gold complexes, only the microtubules of the detached flagellum remained intact. Both gold compounds 1a and 1b feature selective anti-trypanosomal agents and were distinctly more active against T. b. brucei cells than against human HeLa cells. Thus, the gold complexes 1a and 1b feature promising drug candidates for the treatment of trypanosome infections such as sleeping sickness (human African Trypanosomiasis caused by Trypanosoma brucei parasites).

Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean.

Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition.