The iTClamp controls junctional bleeding in a lethal swine exsanguination model.

OBJECTIVE: Severe hemorrhage is a leading cause of death and difficult to control even by trained medical personnel. Current interventions have significant limitations in the prehospital setting; therefore, a need exists for a new and effective treatment. iTraumaCare has designed a temporary wound closure device, the iTClamp, which controls external hemorrhage from open wounds within compressible zones. The device approximates the wound edges, sealing the skin within a pressure bar, enabling creation of a hematoma and subsequent clot formation. The objective of this study is to test the effectiveness of the iTClamp to control external bleeding due to a major vascular injury to the groin in an in vivo swine model. METHODS: Twenty Yorkshire-cross male swine were enrolled in this study. A complex groin injury was created by complete excision of the femoral artery and vein along with some surrounding muscle. The animals were divided into four treatment groups: control (no treatment), early iTClamp treatment, late iTClamp treatment, and standard gauze treatment. Survival rate, survival time, and blood loss were the primary endpoints. Physiologic parameters (heart rate, blood pressure, oxygen saturation) were monitored throughout the experiment and blood samples were collected to analyze partial thromboplastin time and fibrinogen. RESULTS: All (100%) of the animals treated with the iTClamp lived through the end of the experiment, compared to 60% in standard gauze treated and 0% of untreated control animals (early and late iTClamp vs. control and standard gauze, Fisher's exact, p = 0.003). Both the early iTClamp and late iTClamp treatment groups survived significantly longer than the untreated control pigs (Mann-Whitney U-test, p < 0.009). External blood loss was significantly lower in animals treated with the iTClamp (early) compared to no treatment (Mann-Whitney U-test, p < 0.008). There was no significant change in physiologic or hematologic parameters between treatment groups. CONCLUSIONS: The iTClamp showed statistically significant improvement in survival, survival time, and estimated blood loss when compared to no treatment. This proof-of-concept study demonstrates the potential of the iTClamp to control severe bleeding and prevent blood loss.

Evaluation of the iTClamp 50 in a human cadaver model of severe compressible bleeding.

BACKGROUND: Uncontrolled hemorrhage is a significant cause of preventable death. The iTClamp 50 is a temporary wound closure device designed to control bleeding within seconds of an injury. This study evaluates the ability of the iTClamp to control compressible bleeding in a human cadaver model. METHODS: Sterile water was pumped through the major arteries to mimic blood flow. Full-thickness, elliptical segments of skin were excised; arteriotomies or complete transections were performed on the major arteries in the thigh (distal femoral), groin (common femoral), neck (carotid), and arm (brachial). Scalp wounds were created by making a 4.4-cm linear incision to the level of the bone. Fluid losses from the wounds were compared with and without the iTClamp applied and with and without movement of the cadaver. Angiographic images of pressure-injected contrast were obtained of the neck and groin wounds. Hematoma volumes and needle penetration depth into the skin were measured. RESULTS: In all wounds tested, application of the iTClamp significantly reduced fluid loss in all wounds studied (p < 0.05), and movement of the cadaver did not affect the function of the iTClamp. For example, in one groin wound, the average fluid loss during 1 minute was reduced from 728.4 ± 79.3 mL to 5.6 ± 3.4 mL. Distal flow was maintained during application of the iTClamp, as illustrated in angiographic images obtained of the iTClamp applied to the neck and groin wounds. The average needle penetration depth into the skin was 4.21 ± 0.02 mm; furthermore, the iTClamp did not cause any visible skin damage or skin tearing. CONCLUSION: The iTClamp is effective at controlling fluid loss from open wounds within multiple compressible areas. The iTClamp does not occlude distal flow, and aside from small needle punctures, there was no other visible skin damage or skin tearing.

The poxvirus encoded ubiquitin ligase, p28, is regulated by proteasomal degradation and autoubiquitination.

Virus manipulation of the ubiquitin-proteasome system has become increasingly apparent. Ubiquitin is a 76 amino acid protein that is post-translationally conjugated to target proteins, while poly-ubiquitination subsequently leads to degradation via the 26S proteasome. Target specificity is determined by a large family of ubiquitin ligases. Poxviruses encode p28, a highly conserved ubiquitin ligase expressed in a wide range of poxviruses (J. Virol. 79:597). Here we investigate the relationship between p28 and ubiquitination. Confocal microscopy indicated that orthologs of p28 co-localized with ubiquitin at the virus factory. Flow cytometry assays further demonstrated that p28 was regulated by proteasomal degradation. Moreover, when the ubiquitin ligase activity of p28 was disrupted by mutating the RING domain conjugated ubiquitin still localized to the viral factories, indicating that an unknown ubiquitin ligase(s) was responsible for regulating p28. Our observations indicate that p28 is a ubiquitin ligase that is regulated by ubiquitination and proteasomal degradation.

Poxvirus exploitation of the ubiquitin-proteasome system.

Ubiquitination plays a critical role in many cellular processes. A growing number of viruses have evolved strategies to exploit the ubiquitin-proteasome system, including members of the Poxviridae family. Members of the poxvirus family have recently been shown to encode BTB/kelch and ankyrin/F-box proteins that interact with cullin-3 and cullin-1 based ubiquitin ligases, respectively. Multiple members of the poxvirus family also encode ubiquitin ligases with intrinsic activity. This review describes the numerous mechanisms that poxviruses employ to manipulate the ubiquitin-proteasome system.

Control of VP16 translation by the herpes simplex virus type 1 immediate-early protein ICP27.

Herpes simplex virus (HSV) ICP27 is an essential and multifunctional regulator of gene expression that modulates the synthesis and maturation of viral and cellular mRNAs. Processes that are affected by ICP27 include transcription, pre-mRNA splicing, polyadenylation, and nuclear RNA export. We have examined how ICP27 influences the expression of the essential HSV tegument protein and transactivator of immediate-early gene expression VP16. We monitored the effects of ICP27 on the levels, nuclear export, and polyribosomal association of VP16 mRNA and on the amount and stability of VP16 protein. Deletion of ICP27 reduced the levels of VP16 mRNA without altering its nuclear export or the stability of the encoded protein. However, the translational yield of the VP16 mRNA produced in the absence of ICP27 was reduced 9- to 80-fold relative to that for wild-type infection, suggesting a defect in translation. In the absence of ICP27, the majority of cytoplasmic VP16 mRNA was not associated with actively translating polyribosomes but instead cosedimented with 40S ribosomal subunits, indicating that the translational defect is likely at the level of initiation. These effects were mRNA specific, as polyribosomal analysis of two cellular transcripts (glyceraldehyde-3-phosphate dehydrogenase and beta-actin) and two early HSV transcripts (thymidine kinase and ICP8) indicated that ICP27 is not required for efficient translation of these mRNAs. Thus, we have uncovered a novel mRNA-specific translational regulatory function of ICP27.