Human red blood cell acetylcholinesterase activity: a revisit after fifteen years.

Human red blood cell acetylcholinesterase (RBC-AChE) activity is valuable for detecting potential exposure to cholinesterase inhibiting substances (CIS). A reliable population-based RBC-AChE activity reference range is critical for early and massive clinical and occupational toxicology screening. Previous published studies were often limited to small numbers of subjects, various testing methods, and crude statistical data analyses. We tested 4818 adult subjects with a well-established 17-minute modified Michel method over a 2-year period. We conducted a retrospective data analysis and systematically investigated on the influences to testing values from gender, age, age group, and their combinations and interactions. No significant difference was observed in the testing values between males (mean, medium, interquartile range = 0.76, 0.76, 0.71-0.80 ΔpH/h, respectively) and females (mean, medium, interquartile range = 0.76, 0.76, 0.71-0.81 ΔpH/hour, respectively), when gender was the only factor considered (p = 0.7238). However, with age progression, male testing values exhibited a consistent upward trend, while females did not show any clear patterns. Linear regression analysis of the data revealed that gender, age, and age group more or less affected testing values either as independent variables or with their combinations and interactions. However, more potential factors need to be included to achieve better testing value predictions. We recommend the toxicological testing community to adopt a new set of age group specific RBC-AChE activity reference ranges for males (0.68-0.80, 0.69-0.81, 0.70-0.83, 0.71-0.84, and 0.73-0.87 ΔpH/h for 18-29, 30-39, 40-49, 50-59, and ≥60 years old, respectively) while keeping the current reference range (0.63-0.89 ΔpH/hour) for females.

Bioactivity and efficacy of a hyperimmune bovine colostrum product- Travelan, against shigellosis in a non-Human primate model (Macaca mulatta).

Infectious diarrhea is a World Health Organization public health priority area due to the lack of effective vaccines and an accelerating global antimicrobial resistance crisis. New strategies are urgently needed such as immunoprophylactic for prevention of diarrheal diseases. Hyperimmune bovine colostrum (HBC) is an established and effective prophylactic for infectious diarrhea. The commercial HBC product, Travelan® (Immuron Ltd, Australia) targets multiple strains of enterotoxigenic Escherichia coli (ETEC) is highly effective in preventing diarrhea in human clinical studies. Although Travelan® targets ETEC, preliminary studies suggested cross-reactivity with other Gram-negative enteric pathogens including Shigella and Salmonella species. For this study we selected an invasive diarrheal/dysentery-causing enteric pathogen, Shigella, to evaluate the effectiveness of Travelan®, both in vitro and in vivo. Here we demonstrate broad cross-reactivity of Travelan® with all four Shigella spp. (S. flexneri, S. sonnei, S. dysenteriae and S. boydii) and important virulence factor Shigella antigens. Naïve juvenile rhesus macaques (NJRM) were randomized, 8 dosed with Travelan® and 4 with a placebo intragastrically twice daily over 6 days. All NJRM were challenged with S. flexneri 2a strain 2457T on the 4th day of treatment and monitored for diarrheal symptoms. All placebo-treated NJRM displayed acute dysentery symptoms within 24-36 hours of challenge. Two Travelan®-treated NJRM displayed dysentery symptoms and six animals remained healthy and symptom-free post challenge; resulting in 75% efficacy of prevention of shigellosis (p = 0.014). These results strongly indicate that Travelan® is functionally cross-reactive and an effective prophylactic for shigellosis. This has positive implications for the prophylactic use of Travelan® for protection against both ETEC and Shigella spp. diarrheal infections. Future refinement and expansion of pathogens recognized by HBC including Travelan® could revolutionize current management of gastrointestinal infections and outbreaks in travelers' including military, peacekeepers, humanitarian workers and in populations living in endemic regions of the world.

A Hidden Gem: Highlighting the Indispensable Capabilities and History of the DoD Cholinesterase Monitoring Program and DoD Cholinesterase Reference Laboratory.

The DoD Cholinesterase Monitoring Program and Cholinesterase Reference Laboratory have safeguarded U.S. government employees in chemical defense for over five decades. Considering Russia's potential deployment of chemical warfare nerve agents in Ukraine, it is critical to maintain a robust cholinesterase testing program and its efficiency presently and in future.

Acute and two-week inhalation toxicity studies in rats for Polyalphaolefin (PAO) fluid.

Formal occupational exposure limits (OELs) for polyalphaolefin (PAO) fluids have not been proposed. Specific PAO fluids are utilized as aircraft hydraulics or heat sink coolants for electronics and aircraft service air. Toxicity was compared for a PAO fluid in male and female Fischer 344 rats using acute inhalation (0, 100, 500, or 1000 mg/m3 aerosol for 6 hr) and two-week inhalation (0, 20, 100, or 300 mg/m3 aerosol for 6 hr/day, 5 days/week) studies. Neurobehavioral tests following acute exposure showed that both genders were less responsive after exposure to 1000 mg/m3 PAO, and to a lesser extent following 500 mg/m3 PAO. Body weight, food, and water consumption were also affected with recovery after 24 hr. Histopathology for the acute group demonstrated an exposure response increase in severity (minimal to mild) of lesions in the posterior nasal cavities and lungs. Severity of lesions was reduced in the recovery groups (normal to minimal). Acute effects were short-lived and recoverable. Following the two-week exposure, effects were limited to lesions only in the posterior nasal cavities and lungs of the high exposure group, with less severity than in the acute exposure high concentration group. Short-term repeated exposure did not result in any cumulative effects except for minimal respiratory tract changes in the 300 mg/m3 exposure group. Data-driven operational exposure limits (OpELs) were proposed based upon Acute Exposure Guideline Levels process resulting in values of 28, 28, 14, 3.5, and 1.7 mg/m3 for 10 and 30 min, 1, 4, and 8 hr, respectively.

Safety, Pharmacokinetics, and Activity of High-Dose Ivermectin and Chloroquine against the Liver Stage of Plasmodium cynomolgi Infection in Rhesus Macaques.

Previously, ivermectin (1 to 10 mg/kg of body weight) was shown to inhibit the liver-stage development of Plasmodium berghei in orally dosed mice. Here, ivermectin showed inhibition of the in vitro development of Plasmodium cynomolgi schizonts (50% inhibitory concentration [IC50], 10.42 µM) and hypnozoites (IC50, 29.24 µM) in primary macaque hepatocytes when administered as a high dose prophylactically but not when administered in radical cure mode. The safety, pharmacokinetics, and efficacy of oral ivermectin (0.3, 0.6, and 1.2 mg/kg) with and without chloroquine (10 mg/kg) administered for 7 consecutive days were evaluated for prophylaxis or radical cure of P. cynomolgi liver stages in rhesus macaques. No inhibition or delay to blood-stage P. cynomolgi parasitemia was observed at any ivermectin dose (0.3, 0.6, and 1.2 mg/kg). Ivermectin (0.6 and 1.2 mg/kg) and chloroquine (10 mg/kg) in combination were well-tolerated with no adverse events and no significant pharmacokinetic drug-drug interactions observed. Repeated daily ivermectin administration for 7 days did not inhibit ivermectin bioavailability. It was recently demonstrated that both ivermectin and chloroquine inhibit replication of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro Further ivermectin and chloroquine trials in humans are warranted to evaluate their role in Plasmodium vivax control and as adjunctive therapies against COVID-19 infections.

Biosafety and biosecurity requirements for Orientia spp. diagnosis and research: recommendations for risk-based biocontainment, work practices and the case for reclassification to risk group 2.

Scrub typhus is an important arthropod-borne disease causing significant acute febrile illness by infection with Orientia spp.Using a risk-based approach, this review examines current practice, the evidence base and regulatory requirements regarding matters of biosafety and biosecurity, and presents the case for reclassification from Risk Group 3 to Risk Group 2 along with recommendations for safe working practices of risk-based activities during the manipulation of Orientia spp. in the laboratory.We recommend to reclassify Orientia spp. to Risk Group 2 based on the classification for RG2 pathogens as being moderate individual risk, low community risk. We recommend that low risk activities, can be performed within a biological safety cabinet located in a Biosafety Level (BSL) 2 core laboratory using standard personal protective equipment. But when the risk assessment indicates, such as high concentration and volume, or aerosol generation, then a higher biocontainment level is warranted. For, the majority of animal activities involving Orientia spp., Animal BSL 2 (ABSL2) is recommended however where high risk activities are performed including necropsies, Animal BSL (ABSL3) is recommended.

Peste des Petits Ruminants (PPR) virus serological surveillance in goats in Lao PDR: Issues for disease eradication in a low-resource disease-free setting.

Peste des Petits ruminants (PPR) is an economically important transboundary viral disease of goats. This study aimed to determine a baseline of serological evidence for Peste des petits ruminants virus (PPRV) in Lao goats. A total of 1,072 serum samples were collected by convenience sampling across five provinces in Laos and tested for antibody response to PPRV using a commercially available competitive ELISA. Positive antibody responses were found in 2.2% (95% CI 1.4, 3.2) of the samples. True prevalence calculations indicated a total overall sample prevalence of 1.7% (95% CI 0.9, 2.8). The highest provincial seroprevalences were Xiangkhouang (3.5%, 95% CI 1.6, 6.9) and Xayaboury (2.9% (95% CI 1.3, 5.7). There was no association between antibody response and each of the following factors: location, breed, gender or age. Considering the apparent absence of disease manifestation of PPR in Laos, likely explanations for the antibody positivity could include cross reaction to other Morbilliviruses such as Measles or Canine Distemper, importation of pre-vaccinated goats, need for test cut-off re-evaluation to be region specific, or a subclinical and a less virulent circulating virus. This study highlights that the sampled Lao goat population is highly likely to be naïve to PPRV and therefore at risk of an outbreak, possibly by transboundary incursion of livestock from PPR endemic China. Further work is required in the testing of small ruminants in Laos that may eventually provide evidence for a status of freedom from disease, particularly in support of programs aimed at global PPR eradication.

Serosurveillance of Coxiellosis (Q-fever) and Brucellosis in goats in selected provinces of Lao People's Democratic Republic.

Goat raising is a growing industry in Lao People's Democratic Republic, with minimal disease investigation to date, especially zoonoses. This study determined the proportional seropositivity of two zoonotic diseases: Q fever (causative agent Coxiella burnetii) and Brucellosis (Brucella species) in goats across five provinces (Vientiane Capital, Xayaboury, Xiengkhuang, Savannakhet and Attapeu). A total of 1458 goat serum samples were tested using commercial indirect ELISA for both pathogens, plus Rose Bengal agglutination test for Brucellosis. Overall individual seropositivity of C. burnetii was 4.1% and Brucella spp. was 1.4%. A multiple logistic regression model identified that province (Vientiane Capital, p = 0.05), breed (introduced Boer mixed breed, p = 0.006) and age (goats ≥3 years old, p = 0.014) were significant risk factors for C. burnetii seropositivity. The results of the survey indicated that province (Vientiane Capital, p<0.001), breed (introduced Boer mixed breed, p<0.001), production system (commercial, p<0.001), age (adult, p = 0.004), and farm size (large, 0.001) were all significant risk factors seropositivity for Brucella spp. It was concluded that Lao goats have been exposed to both C. burnetii and Brucella spp. however the risk of clinical disease has not yet been determined and there is an urgent need to determine human health risks and economic losses caused by Q fever and Brucellosis.

Neuropathological and behavioral sequelae in IL-1R1 and IL-1Ra gene knockout mice after soman (GD) exposure.

Soman (GD) exposure results in status epilepticus (SE) that leads to neurodegeneration, neuroinflammation, and behavioral consequences including learning and memory deficits. The neuroinflammatory response is characterized by the upregulation of the pro-inflammatory cytokine, interleukin-1 (IL-1), which mediates the expression of other neurotoxic cytokines induced after GD exposure. However, the specific role of IL-1 signaling has not been defined in terms of the consequences of GD-induced SE. Therefore, the purpose of this study was to regulate IL-1 signaling and study the behavioral deficits and neurodegeneration that occur after convulsion onset. Wild type (WT), IL-1 receptor (IL-1R1) knockout (KO), and IL-1 receptor antagonist (IL-1Ra) KO mice were exposed to a convulsive dose of GD, and behavior was evaluated up to 18days later. Activity was studied using the Open Field, anxiety was assessed in the Zero Maze, and spatial learning and memory were evaluated with the Barnes Maze. The animals were euthanized at 24hours and 18days to determine neuropathology in the piriform cortex, amygdala, thalamus, and CA1, CA2/3, and CA4 regions of the hippocampus. Unlike the IL-1Ra KO, the IL-1R1 KO showed less neuropathology compared to WT at 24hours, but moderate to severe injury was found in all strains at 18days. Compared to their saline controls, the exposed WT mice were significantly more active in the Open Field, and the IL-1R1 KO strain showed reduced anxiety in the Zero Maze Test. Compared to WT mice, IL-1R1 and IL-1Ra KO mice had spatial learning and memory impairments in the Barnes Maze. Therefore, the IL-1 signaling pathway affects neurodegeneration and behavior after GD-induced convulsions.

CD4+ Cell infiltration into subcutaneous adipose tissue is not indicative of productively infected cells during acute SHIV infection.

Limited longitudinal data exist on the effect of HIV on adipose tissue (AT). We found an increase in CD4+ cells and detectable SHIV-RNA in AT during acute SHIV infection. SHIV-RNA+ cells were rare, suggesting that AT is unlikely to be a major source of productively infected cells in SHIV infection.

Novel technique for retroperitoneal implantation of telemetry transmitters for physiologic monitoring in Göttingen minipigs (Sus scrofa domesticus).

Telemetric monitoring of physiologic parameters in animal models is a critical component of chemical and biologic agent studies. The long-term collection of neurobehavioral and other physiologic data can require larger telemetry devices. Furthermore, such devices must be implanted in a location that is safe, well-tolerated, and functional. Göttingen minipigs (Sus scrofa domesticus) present an ideal large animal model for chemical agent studies due to their relatively small size, characterized health status, and ease of training and handling. We report an effective approach to implanting a novel device to measure transthoracic impedance to approximate respiratory tidal volume and rate in Suidae. We tested the approach using 24 male Göttingen minipigs. A ventral midline abdominal incision extending from the umbilicus to the prepuce was followed by a paramedian incision of the parietal peritoneum and dorsal blunt dissection to create a retroperitoneal pocket. The device was anchored inside the pocket to the internal abdominal musculature with 3-0 nonabsorbable suture, biopotential leads were routed through the abdominal musculature, and the pocket was closed with 3-0 absorbable suture. Paired biopotential leads were anchored intermuscularly at the level of the seventh rib midway between spine and sternum bilaterally to provide surrogate data for respiratory function. Postoperative recovery and gross pathology findings at necropsy were used to assess safety and refine the surgical procedure. Results demonstrated that this procedure permitted effective monitoring of complex physiologic data, including transthoracic impedance, without negatively affecting the health and behavior of the animals.