Body fluids and salt metabolism - Part I

ABSTRACT: There is a high frequency of diarrhea and vomiting in childhood. As a consequence the focus of the present review is to recognize the different body fluid compartments, to clinically assess the degree of dehydration, to know how the equilibrium between extracellular fluid and intracellular fluid is maintained, to calculate the effective blood osmolality and discuss both parenteral fluid requirments and repair.

Human mast cells express intracellular TRAIL

Recently we demonstrated that human mast cells (MC) express functional TRAIL death receptors. Here we assessed the expression of TRAIL on both mRNA and protein level in cord blood derived MC (CBMC) and HMC-1. The TRAIL release either spontaneous or induced by LPS, IFN-gamma and IgE-dependent activation, was evaluated as well. The protein location was restricted to the intracellular compartment in CBMC, but not in HMC-1. The intracellular TRAIL was not localized inside the granules. The treatment with IFN-gamma and LPS up-regulated intracellular TRAIL expression in CBMC, but did not induce its release. These in vitro data show that human MC can produce and express intracellular TRAIL whose location could not be altered by different stimuli.

Temporal expression of inflammatory mediators in brain basilar artery vasculitis and cerebrospinal fluid of rabbits with coccidioidal meningitis

Strokes due to transmural vasculitis associated with coccidioidal meningitis result in significant morbidity and mortality. The immunological and inflammatory processes responsible are poorly understood. To determine the inflammatory mediators, i.e. cytokines, chemokines, iNOS, matrix metalloproteinase-9 (MMP-9), that possibly contribute to vasculitis, temporal mRNA expression in brain basilar artery samples and MMP-9 protein in the CSF of male NZW rabbits infected intracisternally with 6.5 x 10(4) arthroconidia of Coccidioides immitis were assessed. Five infected and 3 sham-injected rabbits at each time point were euthanized 4, 9, 14 and 20 days post infection. All infected rabbits had neurological abnormalities and severe vasculitis in the basilar arteries on days 9-20. In basilar arteries of infected animals versus controls, mRNAs encoding for IL-6, iNOS, IFN-gamma, IL-2, MCP-1, IL-1beta, IL-10, TNF-alpha, CCR-1, MMP-9, TGF-beta, as well as MMP-9 protein in CSF, were found to be significantly up-regulated. Thus, this study identified inflammatory mediators associated with CNS vasculitis and meningitis due to C. immitis infection. Assessment of the individual contribution of each mediator to vasculitis may offer novel approaches to the treatment of coccidioidal CNS infection. This study also provides unique methodology for immunology studies in a rabbit model.

Distribution of intracellular and secreted surfactant during postnatal rat lung development

Pulmonary surfactant prevents alveolar collapse via reduction of surface tension. In contrast to human neonates, rats are born with saccular lungs. Therefore, rat lungs serve as a model for investigation of the surfactant system during postnatal alveolar formation. We hypothesized that this process is associated with characteristic structural and biochemical surfactant alterations. We aimed to discriminate changes related to alveolarization from those being either invariable or follow continuous patterns of postnatal changes. Secreted active (mainly tubular myelin (tm)) and inactive (unilamellar vesicles (ulv)) surfactant subtypes as well as intracellular surfactant (lamellar bodies (lb)) in type II pneumocytes (PNII) were quantified before (day (d) 1), during (d 7), at the end of alveolarization (d 14), and after completion of lung maturation (d 42) using electron microscopic methods supplemented by biochemical analyses (phospholipid quantification, immunoblotting for SP-A). Immunoelectron microscopy determined the localization of surfactant protein A (SP-A). (1) At d 1 secreted surfactant was increased relative to d 7-42 and then decreased significantly. (2) Air spaces of neonatal lungs comprised lower fractions of tm and increased ulv, which correlated with low SP-A concentrations in lung lavage fluid (LLF) and increased respiratory rates, respectively. (3) Alveolarization (d 7-14) was associated with decreasing PNII size although volume and sizes of Lb continuously increased. (4) The volume fractions of Lb correlated well with the pool sizes of phospholipids in lavaged lungs. Our study emphasizes differential patterns of developmental changes of the surfactant system relative to postnatal alveolarization.

Monomerization of dimeric IgG of intravenous immunoglobulin (IVIg) increases the antibody reactivity against intracellular antigens

Intravenous immunoglobulin (IVIg) preparations are derived from pooled plasma from up to 60,000 healthy human donors and reflect the immunologic experience of the donor population. IVIg contains monomeric and dimeric IgG populations which are in a dynamic equilibrium depending on concentration, pH, temperature, donor pool size, time and stabilizers added in order to keep the portion of dimeric IgG below a certain level. In the present study, monomeric and dimeric fractions were isolated by size exclusion chromatography. The dimeric fractions, however, showed a dynamic instability and tended to dissociate. Both dimeric and monomeric IgG fractions were acid treated (pH 4) in order to dissociate the dimeric IgG. Western-blot analysis identified a sub-population of SDS resistant IgG dimers. Furthermore, the reactivities of the fractions were tested against a panel of self- and exo-antigens. There was a marked increase in activity of the dimeric compared to the monomeric IgG fraction against various intracellular self-antigens. Our data indicates that the increased reactivities of pH 4-treated fractions can mainly be attributed to dimer dissociation, as pH 4-treated monomers do not show significantly increased activities against a range of antigens.

Serum but not follicular fluid cytokine levels are increased in stimulated versus natural cycle IVF: a multiplexed assay study.

Throughout follicular growth the number of immune cells increases, enhanced under stimulation with exogenous gonadotropins. This treatment, however, may adversely influence folliculogenesis and negatively affect oocyte quality through modifications in the follicular concentrations of cytokines released by these immune cells. We studied this hypothesis by systematically analysing the concentrations of cytokines present in the serum and follicular fluid at the time of follicular aspiration in conventional gonadotropin-stimulated (c-IVF) cycles in comparison with natural cycle IVF (NC-IVF) in which the follicles were naturally matured. Our study involved 37 NC-IVF and 39 c-IVF cycles including 13 women who underwent both therapies. Mean age was 35.3 ± 4.6 (SD) and 34.2 ± 3.7 years in the NC-IVF and c-IVF groups (ns). Thirteen cytokines were determined in matched serum and FF samples. Interleukin (IL)-4, TNF-α, RANTES, eotaxin and interferon-gamma-induced protein-10 concentrations were lower in FF than in serum. IL-6, -8, -10, -18, monocyte chemotactic protein-1 (MCP-1), VEGF and leukaemia inhibitory factor (LIF) showed higher median levels in FF than in serum, indicating possible ovarian production. Most of these markers were also increased in concentration in the stimulated (c-IVF) than in the NC groups in the serum, but not in the follicular fluid. This finding can be attributed to the increased number of active follicles present after controlled ovarian stimulation. IL-8 was reduced in c-IVF cycles. Our study did not reveal differences in follicular fluid but in serum cytokine concentrations, suggesting that the follicular immune system might not be significantly affected by gonadotropin stimulation.

Constitutive IL-2 mRNA expression in lymphocytes, infected with the intracellular parasite Theileria parva.

Theileria parva-infected lymphoblastoid cell lines of T or B cell origin were examined for IL-2 mRNA expression. T. parva-infected T cell lines could be of the CD4-CD8-, CD4+CD8-, CD4-CD8+, or CD4+CD8+ phenotype and express alpha beta or gamma delta TCR. By Northern blot analysis and amplification by the polymerase chain reaction, IL-2 mRNA could be detected in all T. parva-infected cell lines tested. IL-2 mRNA expression was also shown to be dependent on the continuous presence of the parasite in the host cell cytoplasm, because elimination of the parasite by treatment of T. parva-infected cell cultures with the theilericidal drug BW720c resulted in the disappearance of detectable IL-2 mRNA. The effect of anti-IL-2 antibodies on the proliferation of T. parva-infected cells was also tested. Inhibition experiments suggest that although IL-2 mRNA can be detected in all cell lines tested, not all T. parva-infected cell lines are dependent on IL-2 for their proliferation. Our data provide the first example for the constitutive expression of IL-2 mRNA in T and B cells caused by infection with an intracellular parasite.

Interference by the intracellular parasite Theileria parva with T-cell signal transduction pathways induces transformation and protection against apoptosis

The intracellular parasite Theileria parva transforms bovine T-lymphocytes, inducing uncontrolled proliferation. Upon infection, cells cease to require antigenic stimulation and exogenous growth factors to proliferate. Earlier studies have shown that pathways triggered via stimulation of the T-cell receptor are silent in transformed cells. This is reflected by a lack of phosphorylation of key signalling molecules and the fact that proliferation is not inhibited by immunosuppressants such as cyclosporin and ascomycin that target calcineurin. This suggests that the parasite bypasses the normal T-cells activation pathways to induce proliferation. Among the MAP-kinase pathways, ERK and p38 are silent, and only Jun N-terminal kinase is activated. This appears to suffice to induce constitutive activation of the transcription factor AP-1. More recently, it could be shown that the presence of the parasite in the host cell cytoplasm also induces constitutive activation of NF-kappaB, a transcription factor involved in proliferation and protection against apoptosis. Activation is effectuated by parasite-induced degradation of IkappaBs, the cytoplasmic inhibitors which sequester NF-kappaB in the cytoplasm. NF-kappaB activation is resistant to the antioxidant N-acetyl cysteine and a range of other reagents, suggesting that activation might occur in an unorthodox manner. Studies using inhibitors and dominant negative mutants demonstrate that the parasite activates a NF-kappaB-dependent anti-apoptotic mechanism that protects the transformed cell form spontaneous apoptosis and is essential for maintaining the transformed state of the parasitised cell.