Optimized wound closure using a biomechanical abdominal model

BACKGROUND

Suturing techniques for midline abdominal wall incisions vary between surgeons. This study uses a biomechanical abdominal model to assess tissue stretch using different suturing techniques for midline laparotomy closure.

METHODS

Deformation tests were performed on the linea alba of 48 porcine abdominal walls. Each pattern was tested three times at pressures ranging from 0 to 20 kPa using different continuous suturing techniques and a control.

RESULTS

There was a sevenfold improvement when the best performing bite separation and bite width ([5, 16] mm) was compared with the most poorly performing combination ([15, 4] mm). The traditional bite and width separation ([10, 10] mm) and the recently proposed combination ([5, 5] mm) may not be optimal, and substantial improvements in surgical outcome may be achieved by changing to a [5,16]-mm combination.

CONCLUSION

These findings suggest using a small bite separation (5 mm) and large bite width (16 mm) during abdominal wound closure may be optimal. Surgical relevance Suturing techniques for midline abdominal wall incisions vary between surgeons. This experimental study suggests substantial potential for improved tissue apposition by changing the suturing approach from the traditional clinical recommendation of 10 mm for both bite separation and bite width to a bite separation of 5 mm and a bite width of 16 mm. These findings support recent European Hernia Society guidelines and the recent randomized STITCH (Suture Techniques to Reduce the Incidence of The inCisional Hernia) trial, which found that small separations are more effective than large separations, but suggest that they should be combined with large bite depths.

Targeting Notch-Activated M1 Macrophages Attenuates Joint Tissue Damage in a Mouse Model of Inflammatory Arthritis

Expression levels of Notch signaling molecules are increased in synovium from patients with rheumatoid arthritis (RA). However, it is not known which cell type(s) in RA synovium have Notch activation or if they play a pathogenetic role in RA. Here, we used Hes1-GFP/TNF-transgenic (TNF-Tg) mice to investigate the role of cells with active Notch signaling (GFP+) in RA. The number of GFP+ cells was significantly increased in synovium in Hes1-GFP/TNF-Tg mice and about 60% of them were F4/80+ macrophages expressing the inflammatory macrophage (M1) marker. TNF-Tg mice transplanted with Hes1-GFP/TNF-Tg bone marrow (BM) had significantly more GFP+ cells in their synovium than in BM. Intraarticular injection of Hes1-GFP/TNF-Tg or Hes1-GFP+ BM macrophages into WT and TNF-Tg mice showed the highest synovial GFP+ cells in the TNF-Tg mice that received Hes1-GFP/TNF-Tg cells. Thapsigargin (THAP), a Notch inhibitor, decreased TNF-induced M1 and increased M2 numbers and reduced joint lesion, synovial M1s, and GFP+ cells in Hes1-GFP/TNF-Tg mice. THAP did not affect M1s from mice carrying a constitutively active Notch1. Thus, the main cells with activated Notch signaling in the inflamed synovium of TNF-Tg mice are M1s derived from BM and targeting them may represent a new therapeutic approach for patients with inflammatory arthritis. © 2017 American Society for Bone and Mineral Research.

Monitoring modulators of platelet aggregation in a microtiter plate assay

Platelets play a central role in maintaining biological hemostasis. Inappropriate platelet activation is responsible for thrombotic diseases such as myocardial infarction and stroke. Therefore, novel agents that can inhibit platelet activation are necessary. However, assays that monitor platelet aggregation are generally time-consuming and require high volumes of blood and specialized equipment. Therefore, a medium- to high-throughput assay that can monitor platelet aggregation would be considered useful. Such an assay should be sensitive, comparable to the "gold standard" assay of platelet aggregometry, and able to monitor multiple samples simultaneously but with low assay volumes. We have developed such a microtiter assay. It can assay an average of 60 independent treatments per 60 ml blood donation and demonstrates greater sensitivity than the current gold standard assay, namely platelet aggregation in stirring conditions in a platelet aggregometer. The microtiter plate (MTP) assay can detect known inhibitors of platelet function such as indomethacin, aspirin, and ReoPro. It is highly reproducible when using standard doses of agonists such as thrombin receptor-activating peptide (20 microM) and collagen (0.19 mg/ml). Finally, the MTP assay is rapid and sensitive and can detect unknown platelet-modulating agents from a library of compounds.

Describing suicidality: an investigation of qualitative SSF responses

Given the incidence and seriousness of suicidality in clinical practice, the need for new and better ways to assess suicide risk is clear. While there are many published assessment instruments in the literature, survey data suggest that these measure are not widely used. One possible explanation is that current quantitatively developed assessment instruments may fail to capture something essential about the suicidal patient's experience. The current exploratory study examined a range of open ended qualitative written responses made by suicidal outpatients to five assessment prompts from the Suicide Status Form (SSF)--psychological pain, press, perturbation, hopelessness, and self-hate. Two different samples of suicidal outpatients seeking treatment, including suicidal college students (n = 119) and active duty U.S. Air Force personnel (n = 33), provided a wide range of written responses to the five SSF prompts. A qualitative coding manual was developed through a step-by-step methodology; two naive coders were trained to use the coding system and were able to sort all the patients' written responses into the content categories with very high interrater reliability (Kappa > .80). Certain written qualitative responses of the patients were more frequent than others, both within and across the five SSF constructs. Among a range of specific exploratory findings, one general finding was that two thirds of the 636 obtained written responses could be reliably categorized under four major content headings: relational (22%), role responsibilities (20%), self (15%), and unpleasant internal states (10%). Theoretical, research, and clinical implications of the methodology and data are discussed.

A systematic, genome-wide, phenotype-driven mutagenesis programme for gene function studies in the mouse

As the human genome project approaches completion, the challenge for mammalian geneticists is to develop approaches for the systematic determination of mammalian gene function. Mouse mutagenesis will be a key element of studies of gene function. Phenotype-driven approaches using the chemical mutagen ethylnitrosourea (ENU) represent a potentially efficient route for the generation of large numbers of mutant mice that can be screened for novel phenotypes. The advantage of this approach is that, in assessing gene function, no a priori assumptions are made about the genes involved in any pathway. Phenotype-driven mutagenesis is thus an effective method for the identification of novel genes and pathways. We have undertaken a genome-wide, phenotype-driven screen for dominant mutations in the mouse. We generated and screened over 26,000 mice, and recovered some 500 new mouse mutants. Our work, along with the programme reported in the accompanying paper, has led to a substantial increase in the mouse mutant resource and represents a first step towards systematic studies of gene function in mammalian genetics.