Inguinal Hernia in Nonhuman Primates: From Asymptomatic to Life-Threatening Events.

In this study, a review of available data and literature on the epidemiology and anamnesis of inguinal hernias in nonhuman primates, as well as on their clinical evaluation and surgical management, was conducted. Inguinal hernias are assumed to be relatively common in male nonhuman primates. Clinical signs are usually limited to a visible or palpable mass in the groin region without pain or systemic illness. Most hernias contain omentum. Careful monitoring is an acceptable treatment option for those animals. Size, the danger of incarceration, and the presence of strangulation are important factors when considering surgical repair. A strangulated inguinal hernia is an emergency, requiring prompt surgery to avoid tissue necrosis and death. Imaging techniques, as well as computed tomography (CT), ultrasonography, and magnetic resonance imaging (MRI), provide information about the anatomical characteristics of the suspected region, allowing for a diagnosis and treatment. An inguinal hernia repair can be performed with either open surgery or laparoscopic surgery. The hernia repair can be achieved by mesh or suture. Decisions regarding which repair technique to use depend on the surgeon's skill level and preference. Complication and recurrence rates are generally low. The most common postsurgical complication is a recurrence of the hernia. Contraceptive measures are not indicated in breeders, as there is no known hereditary component, and the presence of hernia does not appear to affect fertility, nor does it predispose to occurrence, recurrence, or incarceration.

Preperitoneal balloon tamponade and resuscitative endovascular balloon occlusion of the aorta: Alternatives to open packing for pelvic fracture-associated hemorrhage.

BACKGROUND: The objective of this study was to compare the efficacy of preperitoneal balloon tamponade (PPB), resuscitative endovascular balloon occlusion of the orta (REBOA), and open preperitoneal packing (OP) in a realistic animal model of pelvic fracture-associated hemorrhage. METHODS: Thirty-nine swine underwent creation of open-book pelvic fracture and iliac vascular injury. Animals were randomized to no intervention (n = 7), OP (n = 10), PPB (n = 9), zone 1 REBOA (n = 7), and zone 3 REBOA (n = 6) at a mean arterial pressure less than 40 mm Hg from uncontrolled hemorrhage. Primary outcome was survival at 1 hour. Secondary outcomes included survival in the immediate 10 m following intervention reversal, peak preperitoneal pressure (PP), blood loss, bleed rate, and peak lactate. RESULTS: Prior to injury, no difference was measured between groups for weight, hemodynamics, lactate, and hematocrit (all p = NS). The injury was uniformly lethal without intervention, with survival time (mean) of 5 m, peak PP of 14 mm Hg, blood loss of 960 g, bleed rate of 450 g/m, and peak lactate of 2.6 mmol/L. Survival time (m) was extended to 44 with OP, 60 with PPB, and 60 with REBOA (p < 0.01). Peak PP (mm Hg) was 19 with OP, 23 with PPB, 10 with zone 1 REBOA, and 6 with zone 3 REBOA (p < 0.05). Blood loss (g) was 850 with OP, 930 with PPB, 610 with zone 1 REBOA, and 370 with zone 3 REBOA (p < 0.01). Peak lactate (mmol/L) was 3.3 with OP, 4.3 with PPB, 13.4 with zone 1 REBOA, and 5.3 with zone 3 REBOA (p < 0.01). Only 33% of zone 1 REBOA animals survived the initial 10 m after balloon deflation, compared to 60% for OP, 67% for PPB, and 100% for zone 3 REBOA (p < 0.01). CONCLUSION: Preperitoneal balloon tamponade and zone 3 REBOA are effective alternatives to OP in this animal model of lethal pelvic fracture-associated hemorrhage. Zone 1 REBOA extends survival time but with high mortality upon reversal.

Minimally invasive preperitoneal balloon tamponade and abdominal aortic junctional tourniquet versus open packing for pelvic fracture-associated hemorrhage: Not all extrinsic compression is equal.

BACKGROUND: Minimally invasive preperitoneal balloon tamponade (PPB) and abdominal aortic junctional tourniquets (AAJT) have been proposed as alternatives to open preperitoneal packing (OP) for the management of pelvic fracture-associated hemorrhage. We hypothesized that the PPB (SpaceMaker Pro) and AAJT would result in similar rates of survival and blood loss versus OP. METHODS: Thirty-two swine underwent creation of a combined open-book pelvic fracture and major iliac vascular injuries. Animals were randomized to no intervention (n = 7), OP (n = 10), PPB (n = 9), or AAJT (n = 6) at a mean arterial pressure <40 mm Hg following initiation of uncontrolled hemorrhage. Survival (up to 60 minutes + 10 minutes after intervention reversal), hemodynamics, extraperitoneal pressures, blood loss, and associated complications were compared between groups. RESULTS: Prior to injury, no difference was measured between groups for weight, hemodynamics, lactate, and hematocrit (all p > 0.05). The injury was uniformly lethal without intervention, with survival time (mean) of 5 minutes, peak preperitoneal pressure (PP) of 14 mm Hg, blood loss of 960 g, and peak lactate of 2.6 mmol/L. Survival time was 44 minutes with OP versus 60 minutes with PPB and AAJT (p < 0.01). Peak PP (mm Hg) was 19 with OP, 23 with PPB, and 23 with AAJT (p > 0.05). Blood loss (g) was 850 with OP, 930 with PPB, and 600 with AAJT (p > 0.05). Peak lactate (mmol/L) was 3.3 with OP, 4.3 with PPB, and 6.3 with AAJT (p < 0.01). Only 33% of AAJT animals survived intervention reversal versus 60% for OP and 67% for PPB (p < 0.01). Necropsy revealed bowel/bladder injury in 50% of AAJT subjects versus 0% in all other arms (p < 0.01). CONCLUSION: Preperitoneal balloon tamponade is a safe and potentially effective alternative to OP for the management of lethal pelvic fracture-associated hemorrhage. Abdominal aortic junctional tourniquet offers a similar survival benefit to PPB but has concerning rates of ischemia-reperfusion and compressive abdominal organ injury.

Circulating Cytokine/Chemokine Concentrations Respond to Ionizing Radiation Doses but not Radiation Dose Rates: Granulocyte-Colony Stimulating Factor and Interleukin-18.

Exposure to ionizing radiation is a crucial life-threatening factor in nuclear and radiological incidents. It is known that ionizing radiation affects cytokine/chemokine concentrations in the blood of B6D2F1 mice. It is not clear whether radiation dose rates would vary the physiological response. Therefore, in this study we utilized data from two experiments using B6D2F1 female mice exposed to six different dose rates ranging from low to high rates. In one experiment, mice received a total dose of 8 Gy (LD0/30) of 60Co gamma radiation at four dose rates: 0.04, 0.15, 0.30 and 0.47 Gy/min. Blood samples from mice were collected at 24 and 48 h postirradiation for cytokine/chemokine measurements, including interleukin (IL)-1ß, IL-6, IL-10, keratinocyte cytokine (KC), IL-12p70, IL-15, IL-17A, IL-18, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage (GM)-CSF, macrophage (M)-CSF, monokine induced by gamma interferon (MIG), tumor necrosis factor (TNF)-α, fibroblast growth factor (FGF)-basic, vascular endothelial growth factor (VEGF) and platelet-derived growth factor basic (PDGF-bb). At 24 h after ionizing irradiation at dose rate of 0.04 Gy/min, significant increases were observed only in G-CSF and M-CSF ( P < 0.05). At 0.15 Gy/min, IL-10, IL-17A, G-CSF and GM-CSF concentrations were increased. At 0.3 Gy/min, IL-15, IL-18, G-CSF, GM-CSF, M-CSF, MCP-1, MIP-2, MIG, FGF-basic, VEGF and PDGF-bb were significantly elevated ( P < 0.05). At 0.47 Gy/min, IL-6, KC, IL-10, MCP-1, G-CSF, GM-CSF and M-CSF were significantly increased. At 48 h postirradiation, all cytokines/chemokines except MCP-1 returned to or were below their baselines, suggesting these increases are transient at LD0/30 irradiation. Of note, there is a limitation on day 2 because cytokines/chemokines are either at or below their baselines. Other parameters such as fms-like tyrosine kinase receptor-3 ligand (Flt-3 ligand) concentrations and lymphocyte counts, which have proven to be unaffected by radiation dose rates, can be used instead for assessing the radiation dose. However, in a separate radiation dose and time-course experiment, increases in IL-18 and G-CSF depended on the radiation doses but showed no significant differences between 0.58 and 1.94 Gy/min ( P > 0.05) at 3 and 6 Gy but not 12 Gy. G-CSF continued to increase up to day 7, whereas IL-18 increased on day 4 and remained above baseline level on day 7. Therefore, time after irradiation at different doses should be taken into consideration. To our knowledge, these results are the first to suggest that ionizing radiation, even at a very low-dose-rate (0.04 Gy/min), induces circulating G-CSF increases but not others for selected time points; radiation-induced increases in IL-18 at radiation dose rates between 0.15 and 1.94 Gy/min are also not in a radiation dose-rate-dependent manner. C-CSF, lymphocyte counts and circulating Flt-3 ligand should be explored further as possible biomarkers of radiation exposure at early time points. IL-18 is also worthy of further study as a potential biomarker at later time points.

Using Hematology Data from Malaria Vaccine Research Trials in Humans and Rhesus Macaques (Macaca mulatta) To Guide Volume Limits for Blood Withdrawal.

Guidelines on safe volume limits for blood collection from research participants in both humans and laboratory animals vary widely between institutions. The main adverse event that may be encountered in large blood volume withdrawal is iron-deficiency anemia. Monitoring various parameters in a standard blood panel may help to prevent this outcome. To this end, we analyzed the Hgb and MCV values from 43 humans and 46 macaques in malaria vaccine research trials. Although the percentage of blood volume removed was greater for macaques than humans, macaques demonstrated an overall increase of MCV over time, indicating the ability to respond appropriately to frequent volume withdrawals. In contrast, humans showed a consistent declining trend in MCV. These declines in human MCV and Hgb were significant from the beginning to end of the study despite withdrawals that were smaller than recommended volume limits. Limiting the volume withdrawn to no more than 12.5% seemed to be sufficient for macaques, and at 14% or more individual animals tended to fail to respond appropriately to large-volume blood loss, as demonstrated by a decrease in MCV. The overall positive erythropoietic response seen in macaques was likely due to the controlled, iron-fortified diet they received. The lack of erythropoietic response in the human subjects may warrant iron supplementation or reconsideration of current blood volume withdrawal guidelines.