Systemic perturbations in amino acids/amino acid derivatives and tryptophan pathway metabolites associated with murine influenza A virus infection.

BACKGROUND: Influenza A virus (IAV) is the only influenza virus causing flu pandemics (i.e., global epidemics of flu disease). Influenza (the flu) is a highly contagious disease that can be deadly, especially in high-risk groups. Worldwide, these annual epidemics are estimated to result in about 3 to 5 million cases of severe illness and in about 290,000 to 650,000 respiratory deaths. We intend to reveal the effect of IAV infection on the host's metabolism, immune response, and neurotoxicity by using a mouse IAV infection model. METHODS: 51 metabolites of murine blood plasma (33 amino acids/amino acid derivatives (AADs) and 18 metabolites of the tryptophan pathway) were analyzed by using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry with Electrospray Ionization at the acute (7 days post-infection (dpi)), resolution (14 dpi), and recovery (21 dpi) stages of the virus infection in comparison with controls. RESULTS: Among the 33 biogenic amino acids/AADs, the levels of five amino acids/AADs (1-methylhistidine, 5-oxoproline, α-aminobutyric acid, glutamine, and taurine) increased by 7 dpi, whereas the levels of ten amino acids/AADs (4-hydroxyproline, alanine, arginine, asparagine, cysteine, citrulline, glycine, methionine, proline, and tyrosine) decreased. By 14 dpi, the levels of one AAD (3-methylhistidine) increased, whereas the levels of five amino acids/AADs (α-aminobutyric acid, aminoadipic acid, methionine, threonine, valine) decreased. Among the 18 metabolites from the tryptophan pathway, the levels of kynurenine, quinolinic acid, hydroxykynurenine increased by 7 dpi, whereas the levels of indole-3-acetic acid and nicotinamide riboside decreased. CONCLUSIONS: Our data may facilitate understanding the molecular mechanisms of host responses to IAV infection and provide a basis for discovering potential new mechanistic, diagnostic, and prognostic biomarkers and therapeutic targets for IAV infection.

Immunofluorescent characterization of innervation and nerve-immune cell neighborhood in mouse thymus.

The central nervous system impacts the immune system mainly by regulating the systemic concentration of humoral substances, whereas the peripheral nervous system (PNS) communicates with the immune system specifically according to local "hardwiring" of sympathetic/parasympathetic (efferent) and sensory (afferent) nerves to the primary and secondary lymphoid tissue/organs (e.g., thymus spleen and lymph nodes). In the present study, we use immunofluorescent staining of neurofilament-heavy to reveal the distribution of nerve fibers and the nerve-immune cell neighborhood inside the mouse thymus. Our results demonstrate (a) the presence of an extensive meshwork of nerve fibers in all thymic compartments, including the capsule, subcapsular region, cortex, cortico-medullary junction and medulla; (b) close associations of nerve fibers with blood vessels (including the postcapillary venules), indicating the neural control of blood circulation and immune cell dynamics inside the thymus; (c) the close proximity of nerve fibers to various subsets of thymocytes (e.g., CD4+, CD8+ and CD4+CD8+), dendritic cells (e.g., B220+, CD4+, CD8+ and F4/80+), macrophages (Mac1+ and F4/80+) and B cells. Our novel findings concerning thymic innervation and the nerve-immune cell neighborhood in situ should facilitate the understanding of bi-directional communications between the PNS and primary lymphoid organs. Since the innervation of lymphoid organs, including the thymus, may play essential roles in the pathogenesis and progression of some neuroimmune, infectious and autoimmune diseases, better knowledge of PNS-immune system crosstalk should benefit the development of potential therapies for these diseases.

Use of high-resolution fluorescence in situ hybridization for fast and robust detection of SARS-CoV-2 RNAs.

Early, rapid, and accurate diagnostic tests play critical roles not only in the identification/management of individuals infected by SARS-CoV-2, but also in fast and effective public health surveillance, containment, and response. Our aim has been to develop a fast and robust fluorescence in situ hybridization (FISH) detection method for detecting SARS-CoV-2 RNAs by using an HEK 293 T cell culture model. At various times after being transfected with SARS-CoV-2 E and N plasmids, HEK 293 T cells were fixed and then hybridized with ATTO-labeled short DNA probes (about 20 nt). At 4 h, 12 h, and 24 h after transfection, SARS-CoV-2 E and N mRNAs were clearly revealed as solid granular staining inside HEK 293 T cells at all time points. Hybridization time was also reduced to 1 h for faster detection, and the test was completed within 3 h with excellent results. In addition, we have successfully detected 3 mRNAs (E mRNA, N mRNA, and ORF1a (-) RNA) simultaneously inside the buccal cells of COVID-19 patients. Our high-resolution RNA FISH might significantly increase the accuracy and efficiency of SARS-CoV-2 detection, while significantly reducing test time. The method can be conducted on smears containing cells (e.g., from nasopharyngeal, oropharyngeal, or buccal swabs) or smears without cells (e.g., from sputum, saliva, or drinking water/wastewater) for detecting various types of RNA viruses and even DNA viruses at different timepoints of infection.

Bidirectional crosstalk between the peripheral nervous system and lymphoid tissues/organs.

The central nervous system (CNS) influences the immune system generally by regulating the systemic concentration of humoral substances (e.g., cortisol and epinephrine), whereas the peripheral nervous system (PNS) communicates specifically with the immune system according to local interactions/connections. An imbalance between the components of the PNS might contribute to pathogenesis and the further development of certain diseases. In this review, we have explored the "thread" (hardwiring) of the connections between the immune system (e.g., primary/secondary/tertiary lymphoid tissues/organs) and PNS (e.g., sensory, sympathetic, parasympathetic, and enteric nervous systems (ENS)) in health and disease in vitro and in vivo. Neuroimmune cell units provide an anatomical and physiological basis for bidirectional crosstalk between the PNS and the immune system in peripheral tissues, including lymphoid tissues and organs. These neuroimmune interactions/modulation studies might greatly contribute to a better understanding of the mechanisms through which the PNS possibly affects cellular and humoral-mediated immune responses or vice versa in health and diseases. Physical, chemical, pharmacological, and other manipulations of these neuroimmune interactions should bring about the development of practical therapeutic applications for certain neurological, neuroimmunological, infectious, inflammatory, and immunological disorders/diseases.

In vivo imaging and biodistribution of multimodal polymeric nanoparticles delivered to the optic nerve.

The use of nanoparticles for targeted delivery of therapeutic agents to sites of injury or disease in the central nervous system (CNS) holds great promise. However, the biodistribution of nanoparticles following in vivo administration is often unknown, and concerns have been raised regarding potential toxicity. Using poly(glycidyl methacrylate) (PGMA) nanoparticles coated with polyethylenimine (PEI) and containing superparamagnetic iron oxide nanoparticles as a magnetic resonance imaging (MRI) contrast agent and rhodamine B as a fluorophore, whole animal MRI and fluorescence analyses are used to demonstrate that these nanoparticles (NP) remain close to the site of injection into a partial injury of the optic nerve, a CNS white matter tract. In addition, some of these NP enter axons and are transported to parent neuronal somata. NP also remain in the eye following intravitreal injection, a non-injury model. Considerable infiltration of activated microglia/macrophages occurs in both models. Using magnetic concentration and fluorescence visualization of tissue homogenates, no dissemination of the NP into peripheral tissues is observed. Histopathological analysis reveals no toxicity in organs other than at the injection sites. Multifunctional nanoparticles may be a useful mechanism to deliver therapeutic agents to the injury site and somata of injured CNS neurons and thus may be of therapeutic value following brain or spinal cord trauma.

New pathological condition in cultured mulloway Argyrosomus japonicus: histopathological, ultrastructural and molecular studies.

Mulloway Argyrosomus japonicus is a native fish species in Western Australia, for which aquaculture production has recently been developed. A single cohort was stocked in a cage offshore at Geraldton, Western Australia, at a water depth of 6 m. Fish appeared healthy before stocking. Routine histological analysis was carried out from 10 mo post stocking and until completion of harvest (about 2.5 yr post stocking). No gross pathology was evident. Microscopically, however, granulomatous lesions were present in the kidneys of almost 100% of the fish examined. Enclosed in the granuloma was an aggregate of organisms, 4.2 to 5.4 µm in diameter. Kidney granulomas appeared as multi-focal aggregates. Granulomas at different stages of formation and finally fibrosing granulomas were observed. Granulomas also appeared infrequently in other organs: a few granulomas were found in the liver and spleen and a single granuloma in the heart of one fish. Transmission electron microscopy (TEM) revealed that the organism was composed of 2 cells, an outer cell enclosing an inner cell. The inner cell was surrounded by a double membrane and the outer cell by a single membrane. Cellular material, presumably of parasitic nature, surrounded the outer cell. The organism contained primitive mitochondria and abundant free ribosomes. Small subunit ribosomal DNA (SSU rDNA) sequence obtained by PCR revealed an 84% sequence identity with the myxosporean Latyspora scomberomori. Based on TEM and preliminary molecular results, we suggest that the organism is the extrasporogonic developmental stage of a myxozoan parasite, which failed to form spores in the mulloway host.

The first complete papillomavirus genome characterized from a marsupial host: a novel isolate from Bettongia penicillata.

The first fully sequenced papillomavirus (PV) of marsupials, tentatively named Bettongia penicillata papillomavirus type 1 (BpPV1), was detected in papillomas from a woylie (Bettongia penicillata ogilbyi). The circular, double-stranded DNA genome contains 7,737 bp and encodes 7 open reading frames (ORFs), E6, E7, E1, E2, E4, L2, and L1, in typical PV conformation. BpPV1 is a close-to-root PV with L1 and L2 ORFs most similar to European hedgehog PV and bandicoot papillomatosis carcinomatosis virus types 1 and 2 (BPCV1 and -2). It appears that the BPCVs arose by recombination between an ancient PV and an ancient polyomavirus more than 10 million years ago.

High tidal volume ventilation is not deleterious in infant rats exposed to severe hemorrhage.

BACKGROUND: Both high tidal volume (V(T)) ventilation and hemorrhage induce acute lung injury in adult rodents. It is not known whether injurious ventilation augments lung injury in infant rats exposed to severe hemorrhage. METHODS: Two-week-old rats were allocated for ventilation with VT 7 mL/kg and positive end-expiratory pressure (PEEP) 5 cm H2O (low V(T)) or V(T) 21 mL/kg and PEEP 1 (high V(T)) for 4 hours. Additional rats were subjected to volume-controlled hemorrhage and delayed saline resuscitation, followed by low V(T) or high V(T) ventilation for 4 hours. Nonventilated control groups were also included. Airway resistance and the coefficient of tissue elastance were derived from respiratory input impedance measurements using the low-frequency forced oscillation technique. Pressure-volume curves were obtained at baseline and at the end of the study. Interleukin-6, macrophage inflammatory protein-2, and tumor necrosis factor alpha were determined in bronchoalveolar lavage fluid (BALF) and serum. RESULTS: In both healthy and hemorrhage-exposed animals, high V(T) resulted in reduced elastance (better lung compliance) and increased transcutaneous oxygen saturation. Interleukin-6 in BALF was greater in ventilated animals when compared with nonventilated controls, but not different among ventilated groups. No significant differences were found for all other inflammatory mediators, total protein concentration in BALF, and histology. CONCLUSION: High V(T) ventilation with low PEEP improves respiratory system mechanics without causing additional damage to healthy and hemorrhage-exposed infant rats after 4 hours of ventilation. This study highlights the tolerance to high V(T) ventilation in infant rats and underscores the need for age-specific animal models.

Innervation and nerve-immune cell contacts in mouse Peyer's patches.

Neural regulation of the function of the gastrointestinal tract (GIT) relies on a delicate balance of the two divisions of its nervous system, namely, the intrinsic and extrinsic divisions. The intrinsic innervation is provided by the enteric nervous system (ENS), whereas the extrinsic innervation includes sympathetic/parasympathetic nerve fibers and extrinsic sensory nerve fibers. In the present study, we used immunofluorescent staining of neurofilament-heavy (NF-H) to reveal the distribution of nerve fibers and their associations with immune cells inside mouse Peyer's patches (PP), an essential part of gut-associated lymphoid tissue (GALT). Our results demonstrate (1) the presence of an extensive meshwork of NF-H-immunoreactive presumptive nerve fibers in all PP compartments including the lymphoid nodules, interfollicular region, follicle-associated epithelium, and subepithelial dome; (2) close associations/contacts of nerve fibers with blood vessels including high endothelial venules, indicating neural control of blood flow and immune cell dynamics inside the PP; (3) close contacts between nerve fibers/endings and B/T cells and various subsets of dendritic cells ( e.g., B220⁻, B220⁺, CD4⁻, CD4⁺, CD8⁻, and CD8⁺). Our novel findings concerning PP innervation and nerve-immune-cell contacts in situ should facilitate our understanding of bi-directional communications between the PNS and GALT. Since the innervation of the gut, including PP, might be important in the pathogenesis and progression of some neurological, infectious, and autoimmune diseases, e.g., prion diseases and inflammatory bowel disease, better knowledge of PNS-immune system interactions in the GALT (including PP) should benefit the development of potential treatments for these diseases via neuroimmune manipulations.

Distribution of nerve fibers and nerve-immune cell association in mouse spleen revealed by immunofluorescent staining.

The central nervous system regulates the immune system through the secretion of hormones from the pituitary gland and other endocrine organs, while the peripheral nervous system (PNS) communicates with the immune system through local nerve-immune cell interactions, including sympathetic/parasympathetic (efferent) and sensory (afferent) innervation to lymphoid tissue/organs. However, the precise mechanisms of this bi-directional crosstalk of the PNS and immune system remain mysterious. To study this kind of bi-directional crosstalk, we performed immunofluorescent staining of neurofilament and confocal microscopy to reveal the distribution of nerve fibers and nerve-immune cell associations inside mouse spleen. Our study demonstrates (i) extensive nerve fibers in all splenic compartments including the splenic nodules, periarteriolar lymphoid sheath, marginal zones, trabeculae, and red pulp; (ii) close associations of nerve fibers with blood vessels (including central arteries, marginal sinuses, penicillar arterioles, and splenic sinuses); (iii) close associations of nerve fibers with various subsets of dendritic cells, macrophages (Mac1+ and F4/80+), and lymphocytes (B cells, T helper cells, and cytotoxic T cells). Our data concerning the extensive splenic innervation and nerve-immune cell communication will enrich our knowledge of the mechanisms through which the PNS affects the cellular- and humoral-mediated immune responses in healthy and infectious/non-infectious states.

Immunofluorescence characterization of innervation and nerve-immune cell interactions in mouse lymph nodes.

The peripheral nervous system communicates specifically with the immune system via local interactions. These interactions include the "hardwiring" of sympathetic/parasympathetic (efferent) and sensory nerves (afferent) to primary (e.g., thymus and bone marrow) and secondary (e.g., lymph node, spleen, and gut-associated lymphoid tissue) lymphoid tissue/organs. To gain a better understanding of this bidirectional interaction/crosstalk between the two systems, we have investigated the distribution of nerve fibres and PNS-immune cell associations in situ in the mouse lymph node by using immunofluorescent staining and confocal microscopy/ three-dimensional reconstruction. Our results demonstrate i) the presence of extensive nerve fibres in all compartments (including B cell follicles) in the mouse lymph node; ii) close contacts/associations of nerve fibres with blood vessels (including high endothelial venules) and lymphatic vessels/sinuses; iii) close contacts/associations of nerve fibres with various subsets of dendritic cells (e.g., B220+CD11c+, CD4+CD11c+, CD8a+CD11c+, and Mac1+CD11c+), Mac1+ macrophages, and B/T lymphocytes. Our novel findings concerning the innervation and nerve-immune cell interactions inside the mouse lymph node should greatly facilitate our understanding of the effects that the peripheral nervous system has on cellular- and humoral-mediated immune responses or vice versa in health and disease.

A novel virus detected in papillomas and carcinomas of the endangered western barred bandicoot (Perameles bougainville) exhibits genomic features of both the Papillomaviridae and Polyomaviridae.

Conservation efforts to prevent the extinction of the endangered western barred bandicoot (Perameles bougainville) are currently hindered by a progressively debilitating cutaneous and mucocutaneous papillomatosis and carcinomatosis syndrome observed in captive and wild populations. In this study, we detected a novel virus, designated the bandicoot papillomatosis carcinomatosis virus type 1 (BPCV1), in lesional tissue from affected western barred bandicoots using multiply primed rolling-circle amplification and PCR with the cutaneotropic papillomavirus primer pairs FAP59/FAP64 and AR-L1F8/AR-L1R9. Sequencing of the BPCV1 genome revealed a novel prototype virus exhibiting genomic properties of both the Papillomaviridae and the Polyomaviridae. Papillomaviral properties included a large genome size ( approximately 7.3 kb) and the presence of open reading frames (ORFs) encoding canonical L1 and L2 structural proteins. The genomic organization in which structural and nonstructural proteins were encoded on different strands of the double-stranded genome and the presence of ORFs encoding the nonstructural proteins large T and small t antigens were, on the other hand, typical polyomaviral features. BPCV1 may represent the first member of a novel virus family, descended from a common ancestor of the papillomaviruses and polyomaviruses recognized today. Alternatively, it may represent the product of ancient recombination between members of these two virus families. The discovery of this virus could have implications for the current taxonomic classification of Papillomaviridae and Polyomaviridae and can provide further insight into the evolution of these ancient virus families.

Hepatic intranuclear glycogen inclusions in western barred bandicoots (Perameles bougainville).

The western barred bandicoot, Perameles bougainville, is an endangered Australian marsupial species. Routine histology of liver samples collected at necropsy from 19 of 20 (95%) western barred bandicoots revealed the sporadic to common occurrence of abnormal hepatocyte nuclei characterized by margination of chromatin and concomitant central pallor. Some abnormal hepatocyte nuclei were mildly to markedly enlarged and irregularly shaped. Periodic acid-Schiff reagent stained 131 of 142 (92%) of these abnormal hepatocyte nuclei. Positive staining was completely eliminated by diastase pretreatment. Transmission electron microscopy revealed that abnormal hepatocyte nuclei with marginated chromatin did not contain viral particles. Rather, glycogen beta-particles and alpha-rosettes were identified within some abnormal hepatocyte nuclei. Glycogen intranuclear inclusions were an incidental finding in western barred bandicoot hepatocytes.

Clinical chemistry values and tissue enzyme activities in western barred bandicoots (Perameles bougainville).

BACKGROUND: The western barred bandicoot, Perameles bougainville, is an endangered Australian marsupial species whose survival is threatened by a papillomatosis and carcinomatosis syndrome. Investigations to characterize this syndrome would benefit from species-specific clinical chemistry data. OBJECTIVES: The purpose of this study was to determine plasma biochemical reference values and to determine enzyme activities in various tissues of P. bougainville. METHODS: Heparinized blood samples were collected by jugular venipuncture from 53 clinically healthy bandicoots of both sexes and at 3 geographic locations. Plasma was analyzed for routine clinical chemistry variables using an automated biochemistry analyzer. Tissues obtained following humane euthanasia of 3 bandicoots were analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), alpha-amylase (AML), and gamma-glutamyltransferase (GGT) activities. RESULTS: Significant differences in the results were found for animals based on geographic location and sex; hence, results were expressed as minimum and maximum values. A population reference interval was calculated for AST activity (20-283 U/L). ALT was found mainly in the liver, with lower levels in cardiac and skeletal muscle and kidneys. AST was detectable in many tissues, including the heart, liver, kidneys, and central nervous system; CK was found in skeletal and cardiac muscle and central nervous system; AML was found in the pancreas; and GGT was found mainly in kidneys with lower levels in the intestines and pancreas. CONCLUSIONS: These findings will facilitate the interpretation of clinical chemistry results from P. bougainville and thereby inform population management and clinical decision-making.

Immunofluorescent Localization of Non-myelinating Schwann Cells and Their Interactions With Immune Cells in Mouse Thymus.

The thymus is innervated by sympathetic/parasympathetic nerve fibers from the peripheral nervous system (PNS), suggesting a neural regulation of thymic function including T-cell development. Despite some published studies, data on the innervation and nerve-immune interaction inside the thymus remain limited. In the present study, we used immunofluorescent staining of glial fibrillary acidic protein (GFAP) coupled with confocal microscopy/three-dimensional (3D) reconstruction to reveal the distribution of non-myelinating Schwann cells (NMSC) and their interactions with immune cells inside mouse thymus. Our results demonstrate (1) the presence of an extensive network of NMSC processes in all compartments of the thymus including the capsule, subcapsular region, cortex, cortico-medullary junction, and medulla; (2) close associations/interactions of NMSC processes with blood vessels, indicating the neural control of blood flow inside the thymus; (3) the close "synapse-like" association of NMSC processes with various subsets of dendritic cells (DC; e.g., B220+ DCs, CD4+ DCs, and CD8+ DCs), and lymphocytes (B cells, CD4+/CD8+ thymocytes). Our novel findings concerning the distribution of NMSCs and the associations of NMSCs and immune cells inside mouse thymus should help us understand the anatomical basis and the mechanisms through which the PNS affects T-cell development and thymic endocrine function in health and disease.

Distribution of non-myelinating Schwann cells and their associations with leukocytes in mouse spleen revealed by immunofluorescence staining.

The nervous system and the immune system communicate extensively with each other in order to maintain homeostasis and to regulate the immune response. The peripheral nervous system (PNS) communicates specifically with the immune system according to local interactions, including the "hardwiring" of sympathetic/parasympathetic (efferent) and sensory nerves (afferent) to lymphoid tissue and organs. To reveal this type of bidirectional neuroimmune interaction at the microscopic level, we used immunofluorescent staining of glial fibrillary acidic protein (GFAP) coupled with confocal microscopy/3D reconstruction to reveal the distribution of non-myelinating Schwann cells (NMSCs) and their interactions with immune cells inside mouse spleen. Our results demonstrate i) the presence of  an extensive network of  NMSC processes in all splenic compartments including the splenic nodules, periarteriolar lymphoid sheath (PALS), marginal zone,  trabecula, and red pulp; ii) the close association of  NMSC processes with blood vessels (including central artries and their branches, marginal sinuses, penicillar arterioles and splenic sinuses); iii) the close "synapse-like" interaction/association of NMSC processes with various subsets of dendritic cells (DCs; e.g., CD4+CD11c+ DCs, B220+CD11c+ DCs, and F4/80+ CD11c+ DCs), macrophages (F4/80+), and lymphocytes (B cells, CD4+ T helper cells). Our novel findings concerning the distribution of NMSCs and NMSC-leukocytes interactions inside mouse spleen should improve our understanding of the mechanisms through which the PNS affects cellular- and humoral-mediated immune responses in a variety of health conditions and infectious/non-infectious diseases.

Hematologic characteristics of captive western barred bandicoots (Perameles bougainville) from Western Australia.

BACKGROUND: The western barred bandicoot (Perameles bougainville) is an Australian marsupial species now considered endangered as a consequence of habitat destruction and predation. A recently discovered papillomatosis syndrome is hindering efforts to repopulate this species. Hematology reference intervals have been lacking for P bougainville, preventing optimal interpretation of hematology results from wart-affected and clinically normal animals. OBJECTIVES: The purpose of this study was to establish hematology reference values and describe morphologic characteristics of blood cells of healthy western barred bandicoots. METHODS: Fifty-nine whole blood samples were collected by jugular venipuncture into EDTA from 47 clinically healthy captive western barred bandicoots at 3 locations on the Western Australian mainland. A CBC was performed using an ADVIA-120 analyzer. Data were compared on the basis of geographic location, sex, age, and lactation status, and reference intervals were calculated. Blood cell morphology was evaluated using light microscopy, and transmission and scanning electron microscopy. RESULTS: Significant differences were found based on sex (RBC indices, fibrinogen), age (% polychromatophilic RBCs), and geographic location (RBC, neutrophil, and lymphocyte counts, MCHC, % polychromatophilic RBCs, fibrinogen). Combined reference intervals were calculated for hemoglobin concentration (122-165 g/L), HCT (0.36-0.49 L/L), and total WBC (2.9-14.9 x 10(9)/L), monocyte (0-0.6 x 10(9)/L), eosinophil (0-0.9 x 10(9)/L), and total plasma protein (47-63 g/L) concentrations. Leukocyte, erythrocyte, and platelet morphology were similar to those of other marsupial peramelid species. Nuclei in neutrophils, monocytes, and eosinophils occasionally had an annular configuration. CONCLUSIONS: Reference intervals and blood cell morphology obtained in this study will be useful for the evaluation of laboratory data from ill animals and assist with population health monitoring of western barred bandicoots.

Immunofluorescent characterization of non-myelinating Schwann cells and their interactions with immune cells in mouse mesenteric lymph node.

The central nervous system (CNS) influences the immune system in a general fashion by regulating the systemic concentration of humoral substances, whereas the autonomic nervous system communicates specifically with the immune system according to local interactions. Data concerning the mechanisms of this bidirectional crosstalk of the peripheral nervous system (PNS) and immune system remain limited. To gain a better understanding of local interactions of the PNS and immune system, we have used immunofluorescent staining of glial fibrillary acidic protein (GFAP), coupled with confocal microscopy, to investigate the non-myelinating Schwann cell (NMSC)-immune cell interactions in mouse mesenteric lymph nodes. Our results demonstrate i) the presence of extensive NMSC processes and even of cell bodies in each compartment of the mouse mesenteric lymph node; ii) close associations/interactions of NMSC processes with blood vessels (including high endothelial venules) and the lymphatic vessel/sinus; iii) close contacts/associations of NMSC processes with various subsets of dendritic cells (such as CD4+CD11c+, CD8+CD11c+ dendritic cells), macrophages (F4/80+ and CD11b+ macrophages), and lymphocytes. Our novel findings concerning the distribution of NMSCs and NMSC-immune cell interactions inside the mouse lymph node should help to elucidate the mechanisms through which the PNS affects cellular- and humoral-mediated immune responses or vice versa in health and disease.

The synthesis, characterisation and in vivo study of a bioceramic for potential tissue regeneration applications.

Hydroxyapatite (HAP) is a biocompatible ceramic that is currently used in a number of current biomedical applications. Recently, nanometre scale forms of HAP have attracted considerable interest due to their close similarity to the inorganic mineral component of the bone matrix found in humans. In this study ultrafine nanometre scale HAP powders were prepared via a wet precipitation method under the influence of ultrasonic irradiation. The resulting powders were compacted and sintered to form a series of ceramic pellets with a sponge-like structure with varying density and porosity. The crystalline structure, size and morphology of the powders and the porous ceramic pellets were investigated using advanced characterization techniques. The pellets demonstrated good biocompatibility, including mixed cell colonisation and matrix deposition, in vivo following surgical implantation into sheep M. latissimus dorsi.

High tidal volume ventilation does not exacerbate acid-induced lung injury in infant rats.

The impact of mechanical ventilation with high V(T)-low PEEP in infant rats with preinjured lungs is unknown. After tracheal instillation of saline or acid, two week old rats were ventilated with V(T) 7 mL/kg and PEEP 5 cm H2O or V(T) 21 mL/kg and PEEP 1cm H2O for 4 h. Airway resistance and the coefficient of tissue elastance, measured via low-frequency forced-oscillation technique, and quasi-static pressure-volume curves deteriorated less with high V(T)-low PEEP when compared with low V(T)-high PEEP. IL-6 concentration in bronchoalveolar lavage fluid (BALF) did not differ between all ventilated groups. Moreover, differences in BALF protein concentration and histological lung injury scores were independent of applied ventilation strategies. In contrast to experimental studies with adult rats, short-term mechanical ventilation with high V(T)-low PEEP is not deleterious when compared to low V(T)-high PEEP in both healthy and pre-injured infant rat lungs. Our results call for caution when extrapolating data from adult studies and highlight the need for age-specific animal models.