SPI2 T3SS effectors facilitate enterocyte apical to basolateral transmigration of Salmonella-containing vacuoles in vivo.

Salmonella pathogenicity island (SPI) 2 type three secretion system (T3SS)-mediated effector molecules facilitate bacterial survival in phagocytes but their role in the intestinal epithelium in vivo remains ill-defined. Using our neonatal murine infection model in combination with SPI2 reporter technology and RNA-Seq of sorted primary enterocytes, we demonstrate expression of SPI2 effector molecules by intraepithelial Salmonella Typhimurium (S. Typhimurium). Contrary to expectation, immunostaining revealed that infection with SPI2 T3SS-mutants resulted in significantly enlarged intraepithelial Salmonella-containing vacuoles (SCV) with altered cellular positioning, suggesting impaired apical to basolateral transmigration. Also, infection with isogenic tagged S. Typhimurium strains revealed a reduced spread of intraepithelial SPI2 T3SS mutant S. Typhimurium to systemic body sites. These results suggest that SPI2 T3SS effector molecules contribute to enterocyte apical to basolateral transmigration of the SCV during the early stage of the infection.

Functional changes of immune cells: signal of immune tolerance of the ectopic lesions in endometriosis?

RESEARCH QUESTION: What is the potential role of immune cells and their inflammatory cytokines in the pathogenesis, development and establishment of endometriosis? DESIGN: Peritoneal fluid from 59 women (43 with endometriosis and 16 controls) who had undergone laparoscopic surgery was analysed. Changes in the population of innate and adaptive immune cells, cytokines, chemokines and growth factor expression were measured by flow cytometry, Luminex Technology and enzyme-linked immunosorbent assay. RESULTS: No differences were found in the frequencies of the innate and adaptive immune cells between women with and without endometriosis. In the peritoneal fluid of women with endometriosis, IL-1ß, IL-1RN, IL-2, IL-4, IL-8, IL-10, IL-12 (p70), IL-17α, FGF2, G-CSF, MCP-1, MIP-1α and TNF-α were significantly increased compared with controls. A correlation between IL-2, MCP-1, MIP-1α, TNF-α and the severity of endometriosis was observed. The concentration of neopterin, a possible biomarker for this disease, was increased in women with endometriosis compared with controls. CONCLUSIONS: The functional activity of immune cells seemed to be reduced despite their numbers remaining unchanged. The data indicate that a shift of TH cytokine profile occurs, which increases the TH1-TH2 ratio. This is driven by the increased levels of the cytokines (TNF-α and IL-2) in women with severe endometriosis.

Endothelial cells and angiogenesis in the horse in health and disease-A review.

The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.

Cephalometric studies of the mandible, its masticatory muscles and vasculature of growing Göttingen Minipigs-A comparative anatomical study to refine experimental mandibular surgery.

Over many decades, the Göttingen Minipig has been used as a large animal model in experimental surgical research of the mandible. Recently several authors have raised concerns over the use of the Göttingen Minipig in this research area, observing problems with post-operative wound healing and loosening implants. To reduce these complications during and after surgery and to improve animal welfare in mandibular surgery research, the present study elucidated how comparable the mandible of minipigs is to that of humans and whether these complications could be caused by specific anatomical characteristics of the minipigs' mandible, its masticatory muscles and associated vasculature. Twenty-two mandibular cephalometric parameters were measured on CT scans of Göttingen Minipigs aged between 12 and 21 months. Ultimately, we compared this data with human data reported in the scientific literature. In addition, image segmentation was used to determine the masticatory muscle morphology and the configuration of the mandibular blood vessels. Compared to data of humans, significant differences in the mandibular anatomy of minipigs were found. Of the 22 parameters measured only four were found to be highly comparable, whilst the others were not. The 3D examinations of the minipigs vasculature showed a very prominent deep facial vein directly medial to the mandibular ramus and potentially interfering with the sectional plane of mandibular distraction osteogenesis. Damage to this vessel could result in inaccessible bleeding. The findings of this study suggest that Göttingen Minipigs are not ideal animal models for experimental mandibular surgery research. Nevertheless if these minipigs are used the authors recommend that radiographic techniques, such as computed tomography, be used in the specific planning procedures for the mandibular surgical experiments. In addition, it is advisable to choose suitable age groups and customize implants based on the mandibular dimensions reported in this study.

Measurement of the femoral neck angle in medium and large dog breeds using computed tomography.

The aim of this study was to get precise normal values of the femoral neck angle (FNA) in support of developing an optimally functioning total hip prosthesis for medium and large dog breeds. Accordingly, two- and three-dimensional computed tomographic images of the anatomical structures of the proximal femora of 58, hip-dysplasia-free, mature dogs of medium and large breeds were studied. Based on the length of their femora the dogs were allocated to Group I (from 145 to 195 mm) and Group II (from 196 to 240 mm). The FNA was measured on each femur using multi-slice spiral computed tomography (CT). The two- and three-dimensional image data were processed as multi-planar and threedimensional reconstructions using Advantage Workstation software. The CT measurements revealed that Group I had an average femoral neck angle of 147.59° (min. 144.05°, max. 153.35°), while in Group II the average FNA was 147.46° (min. 141°, max. 154.35°). There was no significant correlation between the length of the femur and the FNA in either group. The optimal FNA for a total hip prosthesis is 147.5° for medium and large dog breeds.

Histological and functional comparisons of four anatomical regions of porcine skin with human abdominal skin.

Because of the shortage of human skin for research purposes, porcine skin has been used as a model of human skin. The aim of this study was to identify the region of German Landrace pig skin that could be used as the best possible substitute for human abdominal skin. Porcine samples were collected from the ear, flank, back and caudal abdomen; human abdominal skin samples were excised during plastic surgery. Histological and ultrastructural assessments were carried out on the epidermis and dermis, with emphasis on the dermo-epidermal interface length, dermo-epidermal thickness ratio as well as densities of; hair follicles, arrector pili muscles, blood vessels and sweat glands. In the pig, the barrier function of the four anatomical regions was assessed. Results showed that both histologically and ultrastructurally, all four regions of porcine skin were similar to human skin. These include the shapes of keratinocytes, structure of cell contacts and presence of Weibel Palade bodies in endothelial cells. Other parameters such as the thickness of epidermis, the thickness of stratum basale, spinosum and granulosum and the number of cell layers in the stratum corneum were similar in human abdominal and in all four regions of porcine skin. However, there were also significant differences especially in the thickness of the stratum corneum, the dermo-epidermal interface length and the blood vessel density.

Recommendations of the working group of the Anatomische Gesellschaft on reduction of formaldehyde exposure in anatomical curricula and institutes.

The practice of human and veterinary medicine is based on the science of anatomy and dissection courses are still irreplaceable in the teaching of anatomy. Embalming is required to preserve body donors, for which process formaldehyde (FA) is the most frequently used and well characterized biocidal substance. Since January 2016, a new occupational exposure limit (OEL) for FA of 0.37mg/m3 issued by the European Committee on Hazardous Substances is obligatory since FA has been classified as a human 1B carcinogen. The anatomical institutes in the German-speaking region are called upon to consolidate efforts to reduce use of FA in anatomical curricula and body donations. As a result, the Anatomische Gesellschaft (AG) has formed a "Working Group for Reduction of Formaldehyde Exposure in Dissection Courses" tasked with discussion and recommendation of measures to reduce FA. Based on the assessment of the Working Group, the AG has issued an official opinion to the effect that, at this point in time, embalming of body donors without FA completely is not feasible. Therefore, a combination of approaches are to be used to reduce FA exposure, including technical and structural (architectural) adaptations, modification of protocols for fixation and preservation as well as organizational measures. One structural measure considered unavoidable is the integration of air supply and exhaust of individual dissecting tables into the ventilation system of the anatomy building. To embalm human body donors, intra-arterial perfusion fixation with up to 4% FA and a total fluid volume of 150mL/kg body weight will suffice. For animals where body weights and biology of bodies vary widely (i.e. special needs of fixation for ruminants, large animals as horses) perfusion fixation with up to 4% FA and a quantity of fixative solution of 10-15% of the body weight may be required. Preservation of body donors in storage (immersion) can be done with 40% ethanol or in a full bath preservation containing up to 2% FA. Corpse humidification in the dissecting room is possible with 2% phenoxyethanol, in each case without FA. In veterinary anatomy, microbiological burden is often higher and therefore might lead to a need of FA in long-time storage. Compliance with the current OEL in all institutes would appear to be feasible in combination with various organizational measures.

Arrangement of myofibroblastic and smooth muscle-like cells in superficial peritoneal endometriosis and a possible role of transforming growth factor beta 1 (TGFß1) in myofibroblastic metaplasia.

PURPOSE: Superficial peritoneal endometriotic (pEM) lesions are composed of endometrial glands and stroma, in addition to a third component-myofibroblasts and smooth muscles (SM)-like cells. The latter develops secondary to a metaplasia. In this study, we characterised the third component cells in pEM according to differentiation markers in different micro-compartments. Furthermore, a possible effect of TGFß1 on myofibroblastic metaplasia in endometriotic epithelial cells was studied. METHODS: Seventy-six premenopausal patients were included. Peritoneal biopsies were excised from EM patients (n = 23), unaffected peritoneum (peritoneum from EM patients but without EM components, n = 5/23) and non-EM patients (n = 10). All peritoneal biopsies were immunolabeled for ASMA, calponin, collagen I, desmin, TGFß receptor 1 (R1), R2 and R3 in addition to ultrastructure examination by transmission electron microscopy (TEM) (n = 1). TGFß1 level was measured in peritoneal fluid (PF) (EM, n = 19 and non-EM, n = 13) collected during laparoscopy. Furthermore, TGFß1 effect on myofibroblastic metaplasia was studied in vitro. RESULTS: At the centre of pEM lesions, calponin immunolabeling outweighs the collagen I while in the periphery the reverse occurs. SM-like cells expressing desmin predominate at the periphery, while ASMA immunolabeling was detectable in all micro-compartments. Both indicate an abundance of myofibroblasts at the centre of pEM lesions and SM-like cells in the periphery. Although activated TGFß1 in PF did not differ between EM and non-EM, it inhibited the cell proliferation of the endometriotic epithelial cells and induced an upregulation in ASMA and collagen IA2 expression as well. CONCLUSION: The abundance of the myofibroblasts and SM-like cells points to a myofibroblastic metaplasia in pEM. Both cells are differentially arranged in the different micro-compartments of pEM lesions, with increasing cell maturity towards the periphery of the lesion. Furthermore, TGFß1 may play a role in the myofibroblastic metaplasia of the endometriotic epithelial cells. These findings provide a better insight in the micro-milieu in EM lesions, where most of the disease dynamics occur.

Exploration of serum- and cell culture-derived exosomes from dogs.

BACKGROUND: Exosomes are defined as extracellular membrane vesicles, 30-150 nm in diameter, derived from all types of cells. They originate via endocytosis and then they are released through exocytosis to the extracellular space, being found in various biological fluids as well as in cell culture medium. In the last few years, exosomes have gained considerable scientific interest due to their potential use as biomarkers, especially in the field of cancer research. This report describes a method to isolate, quantify and identify serum- and cell culture-derived exosomes from dog samples, using small volumes (100 µL and 1 mL, respectively). RESULTS: Quantification and sizing of exosomes contained in serum and cell culture samples were assessed by utilizing nanoparticle tracking analysis, transmission electron microscopy and immunoelectron microscopy. Detected particles showed the normal size (30-150 nm) and morphology described for exosomes, as well as presence of the transmembrane protein CD63 known as exosomal marker. CONCLUSIONS: Based on a validated rapid isolation procedure of nanoparticles from small volumes of different types of dog samples, a characterization and exploration of intact exosomes, as well as facilitation for their analysis in downstream applications was introduced.

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view.

BACKGROUND: Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. RESULTS: We quantified cellular uptake of 75 nm diameter citrate stabilized silver NPs (Ag 75 Cit) into an individual human macrophage derived from monocytic THP-1 cells using a FIB/SEM slice and view approach. Cells were treated with 10 µg/ml for 24 h. We investigated a single cell and found in total 3138 ± 722 silver NPs inside this cell. Most of the silver NPs were located in large agglomerates, only a few were found in clusters of fewer than five NPs. Furthermore, we cross-checked our results by using inductively coupled plasma mass spectrometry and could confirm the FIB/SEM results. CONCLUSIONS: Our approach based on FIB/SEM slice and view is currently the only one that allows the quantification of the absolute dose of silver NPs in individual cells and at the same time to assess their intracellular distribution at high resolution. We therefore propose to use FIB/SEM slice and view to systematically analyse the cellular uptake of various NPs as a function of size, concentration and incubation time.

Myofibroblasts Are Evidence of Chronic Tissue Microtrauma at the Endometrial-Myometrial Junctional Zone in Uteri With Adenomyosis.

BACKGROUND: Adenomyosis (AM) uteri exhibit hyperperistalsis. The latter causes a chronic tissue trauma at the endometrial-myometrial junctional zone (EMJZ). Upon tissue trauma, microdehiscences in the myometrium facilitate the translocation of basal endometrial fragments into the myometrium. There, a metaplasia (mediated by transforming growth factor ß1 [TGFß1] and connective tissue growth factor [CTGF]) occurs and AM lesions develop. The abundance of myofibroblasts in a tissue hallmarks metaplasia and points to a tissue microtrauma. MATERIALS AND METHODS: To study if myofibroblasts-as an evidence of tissue microtrauma-are more abundant at EMJZ in AM-uteri, a case-control experimental study was carried out at Charité University Hospital-Endometriosis Research Centre. In all, 18 uteri with AM and 14 uteri without AM were obtained during laparoscopy-assisted vaginal hysterectomy. The immunolabeling of myofibroblastic metaplasia (alpha smooth muscle actin [ASMA] and collagen I), differentiated smooth muscle marker (desmin) and metaplasia mediators (TGF-ß receptors 1, 2, 3 and CTGF) was investigated. The ultrastructure of myofibroblasts at EMJZ of AM uterus was characterized by transmission electron microscopy, in addition to an in vitro study to characterize myofibroblasts in the endometrium of non-AM uterus. RESULTS: Immunolabeling of ASMA and collagen I was significantly higher at EMJZ of AM uteri versus non-AM uteri. Furthermore, myofibroblasts were ultrastructurally characterized at EMJZ of AM. Endometrium of non-AM uterus exhibited 5% to 8% of its cells, expressing ASMA and collagen I. No difference was noted regarding metaplasia mediators immunolabeling between both the groups. CONCLUSION: The abundant and persistent myofibroblasts (expressing ASMA/collagen I) at EMJZ in AM uteri are ultra-/microscopic evidence of chronic tissue trauma. They are of nonmyometrial origin, as they lack desmin immunolabeling.

Ultramicro-trauma in the endometrial-myometrial junctional zone and pale cell migration in adenomyosis.

OBJECTIVE: To determine if ultrastructural tissue trauma occurs in the junctional zone in uteri in adenomyosis. DESIGN: A case-control experimental study. SETTING: Endometriosis research center. PATIENT(S): Twelve uteri with adenomyosis, and 9 uteri without adenomyosis, were gained during laparoscopy-assisted vaginal hysterectomy. INTERVENTION(S): Transmission electron microscopic study of the junctional zone, as well as immunohistochemical staining for epithelial cadherin, and van Gieson staining and immunofluorescence for CD45 and CD68. MAIN OUTCOME MEASURE(S): Analysis of the electron microscopy photos and the immunoreactive scores of the staining. RESULT(S): The inner myometrial muscle fibers were diversely arranged in adenomyosis; they were parallel to the basal endometrial glands in nonadenomyosis. Nuclear membrane infolding of the basal glandular epithelium and the disruption of the interface between basal endometrium and inner myometrium in adenomyosis (but not in nonadenomyosis) were evident. Intraepithelial pale cells were seen in the basal endometrial glands in both groups, but they lacked CD45 and CD68 expression. They were seen actively migrating into the stroma in adenomyosis only. CONCLUSION(S): The myofiber disarray in the inner myometrium, and the nuclear membrane irregularities in adenomyosis, are evidence for ultramicro-trauma in adenomyosis. The migrating nonleukocytic pale cells may be involved in pathogenesis of adenomyosis.

Effects of anticancer drug docetaxel on the structure and function of the rabbit olfactory mucosa.

Docetaxel (DCT) is an anticancer drug which acts by disrupting microtubule dynamics in the highly mitotic cancer cells. Thus, this drug has a potential to affect function and organization of tissues exhibiting high cellular turnover. We investigated, in the rabbit, the effects of a single human equivalent dose (6.26 mg/kg, i.v.) of DCT on the olfactory mucosa (OM) through light and electron microscopy, morphometry, Ki-67 immunostaining, TUNEL assay and the buried food test for olfactory sensitivity. On post-exposure days (PED) 5 and 10, there was disarrangement of the normal cell layering in the olfactory epithelium (OE), apoptotic death of cells of the OE, Bowman's glands and axon bundles, and the presence (including on PED 3) of blood vessels in the bundle cores. A decrease in bundle diameters, olfactory cell densities and cilia numbers, which was most significant on PED 10 (49.3%, 63.4% and 50%, respectively), was also evident. Surprisingly by PED 15, the OM regained normal morphology. Furthermore, olfactory sensitivity decreased progressively until PED 10 when olfaction was markedly impaired, and with recovery from the impairment by PED 15. These observations show that DCT transiently alters the structure and function of the OM suggesting a high regenerative potential for this tissue.

Lung cancer neovascularisation: Cellular and molecular interaction between endothelial and lung cancer cells.

BACKGROUND: Novel vascular-independent conduits have been observed in some cancers. These have been variously described as vasculogenic mimicry, mosaic vessel formation, vascular co-option and intratumour embryonic-like vasculogenesis. Despite lung cancer being the most common cancer worldwide, there is little information on its neovascularisation or the pathways involved. METHODS: An in vitro model involving co-cultures of microvascular lung endothelial cells and squamous or adenocarcinoma lung cancer cells was developed to assess their angiogenic interaction. Cells were incubated and examined by phase contrast microscopy and by immunocytochemistry in both mono- and co-cultures. Cultured cells and lung cancer tissue sections were assessed for new tumour vessel formation, expression of the endothelial marker CD31 and morphology. RESULTS: Lung tumour cells and endothelial cells interacted morphologically via pseudopodia and used alternative pathways to generate new vessels. Co-culturing microvascular endothelial and squamous carcinoma cells led to endothelial cells surrounding tumour cells and the tumour cells being incorporated into vessel walls. Co-culturing endothelial and adenocarcinoma cells resulted in cellular contact and the formation of tumour cell bridges around clusters of endothelial cells. These adencocarcinoma cells became strongly positive for CD31. Tumour tissue section studies supported the in vitro findings. CONCLUSION: Lung carcinoma cells when co-cultured with lung endothelial cells modify their cellular and molecular features that encourage alternative means of providing blood supply. The mechanisms underpinning these non-angiogenic processes need to be further investigated and should be considered when anti-tumour therapeutic interventions are being considered.

Identification of CD133-, CD34- and KDR-positive cells in the bovine ovary: a new site of vascular wall resident endothelial progenitor cells.

Intense angiogenesis, vascular remodelling as well as regression of its vasculature are prerequisites for ovarian function with its cyclically developing and regressing follicles and corpora lutea. So far neither a stringent explanation for the enormous angiogenic potential of the ovary nor its cellular origins have been suggested. In an earlier study of our work group, endothelial cells were isolated from the bovine corpus luteum and cultivated in vitro. They performed vasulogenesis in vitro and showed properties of progenitor cells. The present study aimed at in situ identification of endothelial progenitor cells (EPCs) in the bovine ovary. Immunohistochemical examinations, based on the detection of KDR and CD34 co-labelled cells - a marker combination that amongst others is commonly accepted as typical for EPC identification - were performed. Hormonal cycle dependent expression varieties were analysed by the measurement of mRNA amounts of CD34 and KDR as well as the stem cell marker CD133 (Prominin-1). Ovarian samples comprising corpora lutea of varying stages (developing and mature corpus luteum, corpus luteum in regression, corpus luteum of pregnancy) from 17 adult cows were examined. Results show that specific mRNA of CD133, CD34 and KDR was expressed in ovaries of all luteal stages. Expression data analysis revealed significant differences in CD133 and CD34 expression levels between the luteal stages but no significant differences in KDR expression. CD34/KDR co-immunoreactive cells were predominantly situated within the media of arterial vessel wall. The detection of ovarian EPCs represents an important step towards further understanding of the mechanisms involved in the reproductive biology and pathophysiology of the ovary.

Intussusceptive angiogenesis: a biologically relevant form of angiogenesis.

Angiogenesis, i.e. the development and growth of blood vessels, is a major topic of research as it plays an important role in normal development and in various pathologies. Recent evidence revealed the existence of different mechanisms of blood vessel growth, including sprouting and intussusceptive angiogenesis, vascular mimicry, and blood vessel cooption. The latter two have only been observed in tumor growth, but sprouting and intussusceptive angiogenesis also occur in healthy, physiologically growing tissues. Despite this variety of angiogenic mechanisms, most of the current research is focused on the mechanism of sprouting angiogenesis because this mechanism was first described and because most existing experimental models are related to sprouting angiogenesis. Consequently, the mechanism of intussusceptive angiogenesis is often overlooked in angiogenesis research. Here, the mechanism of intussusceptive angiogenesis is reviewed and the current techniques and models for investigating intussusceptive angiogenesis are summarized. In addition, other mechanisms of vascular growth are briefly reviewed.

Alpha smooth muscle actin in the cycling ovary - an immunohistochemical study.

In the ovary with its cyclically developing and regressing functional bodies and the associated intense neovascularisation and remodelling, alpha-smooth muscle actin (SMA) immunolocalisation has been frequently used as a marker to establish vessel hierarchy, in angiogenesis studies, or in studies characterising ovarian neoplasms in various species. The present study aims at detection of alpha-SMA-immunolocalisation within all structural components of the cycling bovine ovary in order to complement the hitherto available data. 27 ovaries, mainly of dairy cows ranging from 23 to 118 months of age and displaying all major stages of follicle and corpora lutea development, were collected at the abattoir and subjected to routine HE and trichrome staining as well as alpha-SMA immunohistochemistry. For this purpose, the specimens were pooled to form groups of the respective stage of corpus luteum development. The ovarian stroma displayed a notable alpha-SMA-reactivity, particularly surrounding the functional bodies. The study revealed specialised vascular modifications such as multi-directionally arranged vascular smooth muscle layers, vascular sphincters and distinct epitheloid modifications of the media in ovarian arteries. Alpha-SMA-reactivity of the microcirculation within corpora lutea of various stages allowed inferences on respective angiogenic properties. The findings were discussed focussing on functional interpretations.

Limitations of the permeability-limited compartment model in estimating vascular permeability and interstitial volume fraction in DCE-MRI.

Dynamic contrast-enhanced magnetic resonance imaging commonly uses compartment models to estimate tissue parameters in general and perfusion parameters in particular. Compartment models assume a homogeneous distribution of the injected tracer throughout the compartment volume. Since tracer distribution within a compartment cannot be assessed, the parameters obtained by means of a compartment model might differ from the actual physical values. This work systematically examines the widely used permeability-surface-limited one-compartment model to determine the reliability of the parameters obtained by comparing them with their actual values. A computer simulation was used to model spatial tracer distribution within the interstitial volume using diffusion of contrast agent in tissue. Vascular parameters were varied as well as tissue parameters. The vascular parameters used were capillary radius (4 and 12 µm), capillary permeability (from 0.03 to 3.3 µm/s) and intercapillary distances from 30 to 300 µm. The tissue parameters used were tortuosity (λ), porosity (α) and interstitial volume fraction (v(e)). Our results suggest that the permeability-surface-limited compartment model generally underestimates capillary permeability for capillaries with a radius of 4 µm by factors from ≈0.03 for α=0.04, to ≈ 0.1 for α=0.2, to ≈ 0.5 for α=1.0. An overestimation of actual capillary permeability for capillaries with a radius of 12 µm by a factor of ≥1.3 was found for α=1.0, while α=0.2 yielded an underestimation by a factor of ≈0.3 and α=0.04 by a factor of ≈ 0.03. The interstitial volume fraction, v(e), obtained by the compartment model differed with increasing intercapillary distances and for low vessel permeability, whereas v(e) was found to be estimated approximately accurately for P=0.3 µm/s and P=3.3 µm/s for vessel distances <100 µm.

Application of laser postionization secondary neutral mass spectrometry/time-of-flight secondary ion mass spectrometry in nanotoxicology: visualization of nanosilver in human macrophages and cellular responses.

Silver nanoparticles (SNP) are the subject of worldwide commercialization because of their antimicrobial effects. Yet only little data on their mode of action exist. Further, only few techniques allow for visualization and quantification of unlabeled nanoparticles inside cells. To study SNP of different sizes and coatings within human macrophages, we introduce a novel laser postionization secondary neutral mass spectrometry (Laser-SNMS) approach and prove this method superior to the widely applied confocal Raman and transmission electron microscopy. With time-of-flight secondary ion mass spectrometry (TOF-SIMS) we further demonstrate characteristic fingerprints in the lipid pattern of the cellular membrane indicative of oxidative stress and membrane fluidity changes. Increases of protein carbonyl and heme oxygenase-1 levels in treated cells confirm the presence of oxidative stress biochemically. Intriguingly, affected phagocytosis reveals as highly sensitive end point of SNP-mediated adversity in macrophages. The cellular responses monitored are hierarchically linked, but follow individual kinetics and are partially reversible.

Nitrite pickling salt as an alternative to formaldehyde for embalming in veterinary anatomy--A study based on histo- and microbiological analyses.

Formaldehyde, the traditional embalming agent has negative health effects. Nitrite pickling salt has been reported to be a good and inexpensive alternative when supplemented with antioxidants, but the antioxidants caused yellowish colouration of cadavers, and damaged corrosion-resistant steel tables and stone floors. Here, nitrite pickling salt was supplemented with ethanol and Pluriol(®) and tested for effectiveness as an embalming agent of twenty dog cadavers: 10 with open, and 10 with closed abdominal cavity. The texture of the tissue was monitored intermittently for 12 months throughout the course of an anatomical dissection class. Histological and microbiological analysis of samples from muscles, lungs, duodenum and colon were performed. Dogs with an open abdomen remained suitable for dissection purposes during the entire course. The abdominal organs of the closed cadavers lost their natural features, without histological signs of autolysis. Enterococcus spp., Staphylococcus spp., Micrococcus spp., Bacillus spp. and Clostridium perfringens were recorded after 24 weeks. The open cadavers underwent additional maintenance via renewed treatment with ethanol and Pluriol(®) after each dissection. After 30 weeks, C. perfringens was massively reduced in the colon of the open cadavers. The tested solution successfully embalms open bodies, carries no health risks and is environmentally friendly and cost effective.