Safety of Bioplasma FDP and Hemopure in rhesus macaques after 30% hemorrhage.

Objectives: Prehospital transfusion can be life-saving when transport is delayed but conventional plasma, red cells, and whole blood are often unavailable out of hospital. Shelf-stable products are needed as a temporary bridge to in-hospital transfusion. Bioplasma FDP (freeze-dried plasma) and Hemopure (hemoglobin-based oxygen carrier; HBOC) are products with potential for prehospital use. In vivo use of these products together has not been reported. This study assessed the safety of intravenous administration of HBOC+FDP, relative to normal saline (NS), in rhesus macaques (RM). Methods: After 30% blood volume removal and 30 minutes in shock, animals were resuscitated with either NS or two units (RM size adjusted) each of HBOC+FDP during 60 minutes. Sequential blood samples were collected. After neurological assessment, animals were killed at 24 hours and tissues collected for histopathology. Results: Due to a shortage of RM during the COVID-19 pandemic, the study was stopped after nine animals (HBOC+FDP, seven; NS, two). All animals displayed physiologic and tissue changes consistent with hemorrhagic shock and recovered normally. There was no pattern of cardiovascular, blood gas, metabolic, coagulation, histologic, or neurological changes suggestive of risk associated with HBOC+FDP. Conclusion: There was no evidence of harm associated with the combined use of Hemopure and Bioplasma FDP. No differences were noted between groups in safety-related cardiovascular, pulmonary, renal or other organ or metabolic parameters. Hemostasis and thrombosis-related parameters were consistent with expected responses to hemorrhagic shock and did not differ between groups. All animals survived normally with intact neurological function. Level of evidence: Not applicable.

Determining airborne concentrations of spatial repellent chemicals in mosquito behavior assay systems.

BACKGROUND: Mosquito behavior assays have been used to evaluate the efficacy of vector control interventions to include spatial repellents (SR). Current analytical methods are not optimized to determine short duration concentrations of SR active ingredients (AI) in air spaces during entomological evaluations. The aim of this study was to expand on our previous research to further validate a novel air sampling method to detect and quantitate airborne concentrations of a SR under laboratory and field conditions. METHODOLOGY/PRINCIPAL FINDINGS: A thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) method was used to determine the amount of dichlorodiphenyltrichloroethane (DDT) in samples of air. During laboratory experiments, 1 L volumes of air were collected over 10 min intervals from a three-chamber mosquito behavior assay system. Significantly higher levels of airborne DDT were measured in the chamber containing textiles treated with DDT compared to chambers free of AI. In the field, 57 samples of air were collected from experimental huts with and without DDT for onsite analysis. Airborne DDT was detected in samples collected from treated huts. The mean DDT air concentrations in these two huts over a period of four days with variable ambient temperature were 0.74 µg/m(3) (n = 17; SD = 0.45) and 1.42 µg/m(3) (n = 30; SD = 0.96). CONCLUSIONS/SIGNIFICANCE: The results from laboratory experiments confirmed that significantly different DDT exposure conditions existed in the three-chamber system establishing a chemical gradient to evaluate mosquito deterrency. The TD GC-MS method addresses a need to measure short-term (<1 h) SR concentrations in small volume (<100 L) samples of air and should be considered for standard evaluation of airborne AI levels in mosquito behavior assay systems. Future studies include the use of TD GC-MS to measure other semi-volatile vector control compounds.

Dichlorodiphenyltrichloroethane determination in air by thermal desorption gas chromatography-mass spectrometry.

BACKGROUND: Current quantitative methods for airborne dichlorodiphenyltrichloroethane (DDT) require collection and extraction times of ≥ 12 h. The aim of this study was to develop a method for quantifying airborne DDT with a short (<4 h) collection and analysis time. RESULTS: Precision [relative standard deviation (RSD)] for each calibration point (0.8-9.0), linearity (R(2) = 0.99) and apparent recovery (R' = 96.5%) were determined from thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) analyses of Tenax-TA-packed sampling tubes spiked with 1-250 ng of DDT. Recovery of (13) C-labeled 4,4'-DDT from tubes spiked before and after air sampling was 97.3 and 90.3% respectively. DDT was detected and quantified in 1-3 L samples of air collected during 10-180 min sampling events. A significant difference was observed in DDT air concentration between 28 and 33 °C during microchamber studies. CONCLUSIONS: The results demonstrate that the TD GC-MS method developed in this study is precise, reproducible and linear over the span of 1-250 ng of DDT spiked onto TD tubes. By avoiding dilution of the sample, the method described allows the measurement of DDT vapor concentrations during short sampling periods (10-180 min) relevant to mosquito behavior studies.

Cannabichromene and tetrahydrocannabinol determination in mouse blood and brain by gas chromatography-mass spectrometry.

Cannabichromene (CBC) is a phytocannabinoid, the second most abundant cannabinoid quantitatively in marijuana. CBC has been shown to produce antinociception and anti-inflammatory effects in rodents. This method is validated for the measurement of THC and CBC simultaneously after extraction from mouse blood or brain. Whole brain harvested from mice was homogenized 2:1 (v/w) with normal saline. Fifty nanograms of THC-d3 was added to 0.5 mL of heparinized mouse blood, brain homogenate, and THC and CBC fortified blood or brain calibrators, then equilibrated overnight at 5 °C. Two milliliters of "ice cold" acetonitrile was added drop-wise while the sample was vortex mixed, and then the sample was centrifuged and stored overnight at -30 °C. The cannabinoids were extracted from the acetonitrile layer with 2 mL of 0.2 N NaOH and 4 mL of hexane/ethyl acetate (9:1). The solvent was isolated and evaporated to dryness. Trimethylsilyl derivatives were prepared and then analyzed by gas chromatography-mass spectrometry. Linearity in blood and brain of THC and CBC was 2-10,000 ng/mL (ng/g). THC and CBC recovery ranged from 56 to 78% in blood and brain. Precision was demonstrated at 100 ng/mL and 1000 ng/mL with CVs < 15%. The validated method allows for blood and brain concentrations of cannabinoids to be quantificated and correlated with pharmacological effects produced in mice.

Pharmacological evaluation of the natural constituent of Cannabis sativa, cannabichromene and its modulation by Δ(9)-tetrahydrocannabinol.

In contrast to the numerous reports on the pharmacological effects of Δ(9)-tetrahydrocannabinol (THC), the pharmacological activity of another substituent of Cannabis sativa, cannabichromene (CBC) remains comparatively unknown. In the present study, we investigated whether CBC elicits cannabinoid activity in the tetrad assay, which consists of the following four endpoints: hypomotility, antinociception, catalepsy, and hypothermia. Because cannabinoids are well documented to possess anti-inflammatory properties, we examined CBC, THC, and combination of both phytocannabinoids in the lipopolysaccharide (LPS) paw edema assay. CBC elicited activity in the tetrad that was not blocked by the CB(1) receptor antagonist, rimonabant. Moreover, a behaviorally inactive dose of THC augmented the effects of CBC in the tetrad that was associated with an increase in THC brain concentrations. Both CBC and THC elicited dose-dependent anti-inflammatory effects in the LPS-induced paw edema model. The CB(2) receptor, SR144528 blocked the anti-edematous actions of THC, but not those produced by CBC. Isobolographic analysis revealed that the anti-edematous effects of these cannabinoids in combination were additive. Although CBC produced pharmacological effects, unlike THC, its underlying mechanism of action did not involve CB(1) or CB(2) receptors. In addition, there was evidence of a possible pharmacokinetic component in which CBC dose-dependently increased THC brain levels following an i.v. injection of 0.3mg/kg THC. In conclusion, CBC produced a subset of behavioral activity in the tetrad assay and reduced LPS-induced paw edema through a noncannabinoid receptor mechanism of action. These effects were augmented when CBC and THC were co-administered.