Intestinal anastomotic healing models during experimental colitis.

BACKGROUND: Anastomotic leakage represents a major complication following resections in colorectal surgery. Among others, intestinal inflammation such as in inflammatory bowel disease is a significant risk factor for disturbed anastomotic healing. Despite technical advancements and several decades of focused research, the underlying mechanisms remain incompletely understood. Animal experiments will remain the backbone of this research in the near future. Here, instructions on a standardized and reproducible murine model of preoperative colitis and colorectal anastomosis formation are provided to amplify research on anastomotic healing during inflammatory disease. METHODS: We demonstrate the combination of experimental colitis and colorectal anastomosis formation in a mouse model. The model allows for monitoring of anastomotic healing during inflammatory disease through functional outcomes, clinical scores, and endoscopy and histopathological examination, as well as molecular analysis. DISCUSSION: Postoperative weight loss is used as a parameter to monitor general recovery. Functional stability can be measured by recording bursting pressure and location. Anastomotic healing can be evaluated macroscopically from the luminal side by endoscopic scoring and from the extraluminal side by assessing adhesion and abscess formation or presence of dehiscence. Histologic examination allows for detailed evaluation of the healing process. CONCLUSION: The murine model presented in this paper combines adjustable levels of experimental colitis with a standardized method for colorectal anastomosis formation. Extensive options for sample analysis and evaluation of clinical outcomes allow for detailed research of the mechanisms behind defective anastomotic healing.

Magnetostructural coupling in RFeO3 (R = Nd, Tb, Eu and Gd).

We investigate the interplay of magnetization and lattice vibrations in rare-earth orthoferrites RFeO3, with a specific focus on non-symmetry-breaking anomalies. To do so, we study the magnetization, magnon excitations and lattice dynamics as a function of temperature in NdFeO3, TbFeO3, EuFeO3 and GdFeO3. The magnetization shows distinct temperature anomalous behavior for all investigated rare-earth orthoferrites, even in the compounds with no phase transitions occurring at those temperatures. Through spin-phonon coupling, these magnetic changes are mirrored by the FeO6 rotation mode for all the studied RFeO3, revealing a common magnetostructural effect associated with the octahedra rotations. The R3+ oscillation modes evidence a Fe3+/R3+ spins cross-talk for the NdFeO3 and TbFeO3 cases. Our work sheds light into the common magnetostructural coupling in rare-earth orthoferrites, and the important role of magnetic anisotropy and spin-orbit coupling strength of the R-Fe interactions on the spin-reorientation transition at high temperatures.

Resistance to inflammation underlies enhanced fitness in clonal hematopoiesis.

Clonal hematopoiesis results from enhanced fitness of a mutant hematopoietic stem and progenitor cell (HSPC), but how such clones expand is unclear. We developed a technique that combines mosaic mutagenesis with color labeling of HSPCs to study how acquired mutations affect clonal fitness in a native environment. Mutations in clonal hematopoiesis­associated genes such as asxl1 promoted clonal dominance. Single-cell transcriptional analysis revealed that mutations stimulated expression of proinflammatory genes in mature myeloid cells and anti-inflammatory genes in progenitor cells of the mutant clone. Biallelic loss of one such immunomodulator, nr4a1, abrogated the ability of asxl1-mutant clones to establish clonal dominance. These results support a model where clonal fitness of mutant clones is driven by enhanced resistance to inflammatory signals from their mutant mature cell progeny.

Interconversion of multiferroic domains and domain walls.

Systems with long-range order like ferromagnetism or ferroelectricity exhibit uniform, yet differently oriented three-dimensional regions called domains that are separated by two-dimensional topological defects termed domain walls. A change of the ordered state across a domain wall can lead to local non-bulk physical properties such as enhanced conductance or the promotion of unusual phases. Although highly desirable, controlled transfer of these properties between the bulk and the spatially confined walls is usually not possible. Here, we demonstrate this crossover by confining multiferroic Dy0.7Tb0.3FeO3 domains into multiferroic domain walls at an identified location within a non-multiferroic environment. This process is fully reversible; an applied magnetic or electric field controls the transformation. Aside from expanding the concept of multiferroic order, such interconversion can be key to addressing antiferromagnetic domain structures and topological singularities.

A receptor for the lipocalin placental protein 14 on human monocytes.

Human placental protein 14 (PP14), a member of the lipocalin structural superfamily, is an abundant amniotic fluid glycoprotein with documented immunoinhibitory activities. While receptors have been characterized for several other lipocalins, none have been reported to date for PP14. In the present study, two-color immunofluorescence and flow cytometry was used to screen peripheral blood mononuclear cell subpopulations for their capacity to engage fluoresceinated recombinant PP14. The tagged PP14 bound strongly in a specific and saturable fashion to CD14+ (monocyte lineage) cells, but not to CD20+ (B cell lineage) or CD3+ (T cell lineage) cells. This binding was both pH- and temperature-sensitive, and was reduced by proteolytic pre-digestion of the cells with trypsin or proteinase K. Scatchard analysis demonstrated a single class of receptors on CD14+ cells, with a K(D) of approximately 1 x 10(-8) and approximately 10-35,000 receptors per cell. These findings constitute the first report of a cell surface-associated binding protein for PP14 and set the stage for exploring the molecular mechanisms of PP14-mediated signaling and immunomodulation.

Isolation and characterization of BHK cells sensitive to ionizing radiation and alkylating agents.

A host-cell viral suicide enrichment procedure was used to isolate BHK strains sensitive to ionizing radiation. Of six strains surviving infection with irradiated herpes simplex virus (HSV), three were found to be more sensitive to ionizing radiation than the parental BHK cells. Thus the D0's of strains V1, V2, and V5 were 1.59, 1.41, and 1.49 Gy, respectively, while the D0 for the parental BHK strain was 1.79. Strains V1 and V2 were studied in more detail and found to exhibit hypersensitivity to ethyl methanesulfonate (EMS), methyl methanesulfonate, and N-methyl-N'-nitro-N-nitrosoguanidine, but not to uv radiation. Susceptibility to mutation in response to EMS was also compared in BHK and strains V1 and V2. The frequency of induction of ouabain-resistant cells was 140% of the parental strain in the case of strain V1 and 58% of the parental strain in the case of strain V2.

Distribution and extent of schistosomiasis in female pelvic organs, with special reference to the genital tract, as determined at autopsy.

PIP: Tissue samples were taken in a series of 64 consecutive autopsies of African women aged 16-70 years. These were block-dissected and studied to determine the frequency of schistosome eggs in tissues of the uterus, and its adnexa, and in the vagina, as well as to determine the numbers of eggs in these tissues. In addition, by histological examination, it was hoped that the frequency and degree of inflammation accompanying the eggs' presence could be learned. 37 of 64 autopsy specimens showed evidence of schistosomiasis. In terms of the mean number of eggs per gram of tissue, the heaviest deposition of eggs was in the bladder. The cervix, uteri, fallopian tubes, and ovaries had eggs to much the same degree, leaving the myometrium and parametrium with the fewest eggs resident. Rectal tissue was relatively clean, surprizingly. Tissues of pelvic organs were positive for schistosome eggs in a total of 37: 33 by digestion technique, 24 by histology, and 20 by both. Inflammatory changes associated with schistosome eggs were found in 12 of 24 infections discovered histologically. Inflammation in the gential tract was only found in 3 cervixes and 2 vaginal walls; in bladders for example, infectious inflammation was seen in 7. Eggs of S. haematobium were identified in 19 of 24 histologically discovered infections. Eggs of S. haematobium were found in all 33 instances identified by the digestion technique, and in 9 of these instances, eggs of S. mansoni were also found. 7 of 9 infections with S. mansoni were of the rectum and 2 were of the bladder.^ieng

Schistosomiasis of the male pelvic organs. Severity of infection as determined by digestion of tissue and histologic methods in 300 cadavers.

PIP: In order to assess the effects of schistosomiasis in the prostate gland, seminal vesicles, and the intraabdominal portion of the vas deferens, we examined these organs at 200 consecutive autopsies of African males. Portions of these organs as well as of the bladder, were digested in KOH; the proportion of eggs of Schistosoma haematobium found in these organs was: seminal vesicles, 54.5%, spermatic duct, 39.9%, and prostate gland, 20.5%. Eggs of Schistosoma mansoni were rarer in these tissues (bladder, 1%; seminal vesicles, 15.5%; spermatic duct, 8%; and prostate gland, 1%). The mean number of S. haematobium eggs/gm of tissue was substantially greater than for S. mansoni. To compare the histologic technique with that of digestion of tissue, we studied a further 100 consecutive autopsies--77% showed evidence of schistosomiasis by 1 or the other method. The bladder was affected in 65%; prostate gland, 21%, seminal vesicle, 70%; and the vas deferens in 42%. The detection of schistosomiasis was almost as good by the traditional histologic as by the digestion technique. Neither method revealed all infections. The frequency and severity of the lesions in these tissues was studied by standard histologic technique: tissues from the last 100 consecutive cases showed definite inflammatory lesions especially in the seminal vesicles, but less than in the prostate gland. In none, however, was the reaction marked. There was good correlation between the mean number of eggs by the histologic and digestion methods, the exception being the prostate gland. No correlation could be shown between the number of eggs and inflammation; only a few eggs may provoke a marked response or the reverse may occur. Eggs were found mainly in the muscle layer of the seminal vesicles, but also in the mucosa and even the lumen. The number of eggs did not vary much with age of infected person; however after age 60 the mean number of eggs in the bladder and seminal vesicles dropped markedly.^ieng