Structural changes in collagen and aggrecan during extended aging may improve beef tenderness.

The aim of this study was to characterize structural and property modifications of intramuscular connective tissue (IMCT) during extended aging. Longissimus lumborum (LL), Gluteus medius (GM), and Gastrocnemius (GT) muscles were collected from 10 USDA choice carcasses, fabricated and assigned to one of four aging periods: 3, 21, 42, or 63 days (n = 120). As expected, tenderness improved, and IMCT texture weakened after 21 days of postmortem aging (dpm; P < 0.05). In addition, transition temperature of collagen decreased (P < 0.01) after 42 dpm. It is interesting to note the collagen structure was also altered where relative % of γ chain decreased after 42 dpm (P < 0.05), and the α1 chain % increased at 63 days (P < 0.01). Finally, The LL and GT had a decrease in the 75 kDa aggrecan fragments from 3 to 21 to 42 dpm (P < 0.05). This study provided evidence that IMCT weakens during postmortem aging due to the modifications of IMCT components such as collagen and proteoglycan.

Ambient and Dosed Exposure to Quaternary Ammonium Disinfectants Causes Neural Tube Defects in Rodents.

BACKGROUND: Quaternary ammonium compounds are a large class of chemicals used for their antimicrobial and antistatic properties. Two common quaternary ammonium compounds, alkyldimethylbenzyl ammonium chloride (ADBAC) and didecyldimethyl ammonium chloride (DDAC), are combined in common cleaners and disinfectants. Introduction of a cleaner containing ADBAC+DDAC in the vivarium caused neural tube defects (NTDs) in mice and rats. METHODS: To further evaluate this finding, male and female mice were dosed in the feed at 60 or 120 mg/kg/day, or by oral gavage at 7.5, 15, or 30 mg/kg ADBAC+DDAC. Mice also received ambient exposure to ADBAC+DDAC from the disinfectant used in the mouse room. Embryos were evaluated on gestational day 10 for NTDs, and fetuses were evaluated on gestational day 18 for gross and skeletal malformations. RESULTS: We found increased NTDs with exposure to ADBAC+DDAC in both rats and mice. The NTDs persisted for two generations after cessation of exposure. Notably, male exposure alone was sufficient to cause NTDs. Equally significant, ambient exposure from disinfectant use in the vivarium, influenced the levels of NTDs to a greater extent than oral dosing. No gross or significant axial skeletal malformations were observed in late gestation fetuses. Placental abnormalities and late gestation fetal deaths were increased at 120 mg/kg/day, which might explain the lack of malformations observed in late gestation fetuses. CONCLUSION: These results demonstrate that ADBAC+DDAC in combination are teratogenic to rodents. Given the increased use of these disinfectants, further evaluation of their safety in humans and their contribution to health and disease is essential. Birth Defects Research 109:1166-1178, 2017. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

Exploratory Studies With BT-11: A Proposed Orally Active Therapeutic for Crohn's Disease.

Lanthionine synthetase cyclase-like receptor 2 (LANCL2) is a novel therapeutic target for Crohn's disease (CD). BT-11 is a small molecule that binds LANCL2, is orally active, and has demonstrated therapeutic efficacy in 3 validated mouse models of colitis at doses as low as 8 mg/kg/d. Exploratory experiments evaluated BT-11 in male Harlan Sprague Dawley rats with a single oral dose of 500 mg/kg and 80 mg/kg/d for 14 days (n = 10 rats dosed/group). Treated and control rats were observed for behavioral detriments, and blood and tissues were collected for clinical pathology and histopathological examination. A functional observational battery demonstrated no differences between treated and control groups over multiple times of observation for quantal, categorical, and continuous end points, including posture, in cage activity, approach, response to touch, weight, grip strength, body temperature, and time on a rotarod. Histopathological examination of the brain, kidney, liver, adrenal gland, testes, stomach, small and large intestines, duodenum, pancreas, heart, lungs, spleen, thymus, and rib found no significant differences between the groups. Plasma enzymes associated with liver function were transiently elevated 2 to 4 days after the 500 mg/kg single dose but returned to normal values by 8 days and were not observed at any time in rats given 80 mg/kg/d for 14 days. One hour after oral administration of a single dose of 80 mg/kg, BT-11 had a maximal concentration of 21 ng/mL; the half-life was 3 hours. These experimental results demonstrated that BT-11 is well tolerated in rats, and, with further testing, may hold promise as an orally active therapeutic for CD.

Cefazolin concentration in surgically created wounds treated with negative pressure wound therapy compared to surgically created wounds treated with nonadherent wound dressings.

OBJECTIVE: To compare cefazolin concentrations in biopsied tissue samples collected from surgically created wounds treated with negative pressure wound therapy to those collected from surgically created wounds treated with nonadherent dressings. STUDY DESIGN: Prospective, controlled, experimental study. ANIMALS: Adult female spayed Beagles (n = 12). METHODS: Full thickness cutaneous wounds were created on each antebrachium (n = 24). Immediately after surgery, cefazolin (22 mg/kg intravenously [IV]) was administered to each dog and continued every 8 hours during the study. The right wound was randomly assigned to group I or group II whereas the wound on the contralateral antebrachium was assigned to the other group. Group I wounds were treated with negative pressure wound therapy (NPWT) and group II wounds were treated with nonadherent dressings for 3 days. Dressings were changed and tissue biopsies obtained from wound beds at 24 hours intervals for both groups. Cefazolin wound tissue and plasma concentrations were measured by liquid chromatography mass spectrometry (LC-MS/MS). Blood samples for measuring plasma cefazolin concentrations were collected before biopsy sampling. At the time of surgery and at each subsequent bandage change, wound beds were swabbed and submitted for aerobic and anaerobic culture. RESULTS: After initiating cefazolin treatment, wound tissue antibiotic concentrations between treatment groups were not significantly different at any sampling time. Similarly, after initiating cefazolin treatment, plasma cefazolin concentrations were not significantly different at any sampling time for individual dogs. CONCLUSIONS: Using a canine experimental model, NPWT treatment of surgically created wounds does not statistically impact cefazolin tissue concentrations when compared with conventional nonadherent bandage therapy.

Comparison of two blood-brain barrier in vitro systems: cytotoxicity and transfer assessments of malathion/oxon and lead acetate.

Toxicity and integrity disruption in response to transport through the blood-brain barrier (BBB) of the organophosphates malathion and malaoxon and heavy metal lead acetate were assessed in two in vitro barrier systems. One system was constructed using bovine brain microvascular endothelial cells (BMEC), while the other system was constructed with rat brain microvascular endothelial cells (RBE4); both were cocultured with rat astrocytes. We hypothesized that these models would respond differently to neurotoxic compounds. Concentrations of malathion, malaoxon, and lead acetate between 0.01 microM and 1 mM were assessed for their capacity to cause cytotoxicity to the astrocytes and endothelial cells utilized to construct the BBB systems, with the least cytotoxic concentrations chosen for transfer assessments of neurotoxicants through the barrier systems. Concentrations of malathion at 10 microM, malaoxon at 1 microM, and lead acetate at 1 and 10 microM were selected. Lead concentrations were measured in media of the abluminal and luminal sides of both systems using graphite furnace atomic absorption at the beginning of the treatment (T0) and 14 h later (T14). Passage of organophosphate compounds was determined utilizing inhibition of acetylcholinesterase enzyme in a neuroblastoma cell line (SH-SY5Y) localized below the barrier system. Transendothelial electrical resistance was assessed as a measurement of integrity of the barrier systems, with baseline values higher with the RBE4-astrocyte system than with the BMEC-astrocyte system. Metabolic capability, as measured by esterase activity, was higher in BMECs, which were more likely to retain lead than RBE4 cells. Results suggest that differences in endothelial cell source can affect the outcome of studies on toxicant transfer through in vitro BBB systems.