Genetic models in applied physiology: selected contribution: effects of spaceflight on immunity in the C57BL/6 mouse. II. Activation, cytokines, erythrocytes, and platelets.

This portion of the study quantified the effects of a 12-day space shuttle mission (Space Transport System-108/UF-1) on body and lymphoid organ masses, activation marker expression, cytokine secretion, and erythrocyte and thrombocyte characteristics in C57BL/6 mice. Animals in flight (Flt group) had 10-12% lower body mass compared with ground controls housed either in animal enclosure modules or under standard vivarium conditions (P < 0.001) and the smallest thymus and spleen masses. Percentages of CD25(+) lymphocytes, CD3(+)/CD25(+) T cells, and NK1.1(+)/CD25(+) natural killer cells from Flt mice were higher compared with both controls (P < 0.05). In contrast, CD71 expression was depressed in the Flt and animal enclosure module control mice compared with vivarium control animals (P < 0.001). Secretion of interferon-gamma, IL-2, and IL-4, but not tumor necrosis factor-alpha and IL-5, by splenocytes from Flt mice was decreased relative to either one or both ground controls (P < 0.05). Flt mice also had high red blood cell and thrombocyte counts compared with both sets of controls; low red blood cell volume and distribution width, percentage of reticulocytes, and platelet volume were also noted (P < 0.05) and were consistent with dehydration. These data indicate that relatively short exposure to the spaceflight environment can induce profound changes that may become significant during long-term space missions.     

Garlic compounds modulate macrophage and T-lymphocyte functions

Organosulfur compounds of garlic have been shown to inhibit growth of animal tumors and to modulate the activity of diverse chemical carcinogens. There is also evidence that garlic may modulate antitumor immunity. In this study, we determined the effects of an aqueous garlic extract and a protein fraction isolated from the extract on the chemiluminescent oxidative burst of the murine J774 macrophage cell line and thioglycollate-elicited peritoneal macrophages obtained from BALB/c mice. T-lymphocyte activity was determined using mouse splenocytes incubated with phytohemagglutinin, labeled with [3H]-thymidine and assayed for lymphoproliferation. Significant dose-related augmentation of oxidative burst was observed with garlic extract and the protein fraction. The protein fraction also enhanced the T-lymphocyte blastogenesis. The data suggest that garlic compounds may serve as biological response modifiers by augmenting macrophage and T-lymphocyte functions.     

Segmentation defects of Notch pathway mutants and absence of a synergistic phenotype in lunatic fringe/radical fringe double mutant mice

The Notch signaling pathway is important in regulating formation and anterior-posterior patterning of somites in vertebrate embryos. Here we show that distinct segmentation defects are displayed in embryos mutant for the Notch pathway genes Notch1, Lunatic fringe (Lfng), Delta-like 1 (Dll1), and Delta-like 3 (Dll3). Lfng-deficient mice and Dll3-deficient mice exhibit very similar defects, and marker analysis suggests that progression of the segmentation clock is disrupted in Dll3 mutants. We also show that Radical fringe (Rfng)-deficient mice exhibit no obvious phenotypic defects. To assess whether the absence of a phenotype in Rfng-deficient mice was the result of functional redundancy with the Lfng gene, we generated Lfng/Rfng double homozygous mutant mice. These mice exhibit the skeletal defects normally observed in Lfng-deficient mice, but we detected no obvious synergistic or additive effects in the double mutant animals.     

A murine model for bone loss from therapeutic and space-relevant sources of radiation.

Cancer patients receiving radiation therapy are exposed to photon (gamma/X-ray), electron, and less commonly proton radiation. Similarly, astronauts on exploratory missions will be exposed to extended periods of lower-dose radiation from multiple sources and of multiple types, including heavy ions. Therapeutic doses of radiation have been shown to have deleterious consequences on bone health, occasionally causing osteoradionecrosis and spontaneous fractures. However, no animal model exists to study the cause of radiation-induced osteoporosis. Additionally, the effect of lower doses of ionizing radiation, including heavy ions, on general bone quality has not been investigated. This study presents data developing a murine model for radiation-induced bone loss. Female C57BL/6 mice were exposed to gamma, proton, carbon, or iron radiation at 2-Gray doses, representing both a clinical treatment fraction and spaceflight exposure for an exploratory mission. Mice were euthanized 110 days after irradiation. The proximal tibiae and femur diaphyses were analyzed using microcomputed tomography. Results demonstrate profound changes in trabecular architecture. Significant losses in trabecular bone volume fraction were observed for all radiation species: gamma, (-29%), proton (-35%), carbon (-39%), and iron (-34%). Trabecular connectivity density, thickness, spacing, and number were also affected. These data have clear implications for clinical radiotherapy in that bone loss in an animal model has been demonstrated at low doses. Additionally, these data suggest that space radiation has the potential to exacerbate the bone loss caused by microgravity, although lower doses and dose rates need to be studied.     

Atypical clinical presentation of a subset of patients with anti-RNA polymerase III - non-scleroderma cases associated with dominant RNA polymerase i reactivity and nucleolar staining

Introduction

Anti-RNA polymerase III (RNAP III) antibodies are highly specific markers of scleroderma (systemic sclerosis, SSc) and associated with a rapidly progressing subset of SSc. The clinical presentation of anti-RNAP III positive patients, onset of Raynaud's phenomenon (RP) and SSc in unselected patients in a rheumatology clinic were evaluated.

Methods

Autoantibodies in sera from 1,966 unselected patients (including 434 systemic lupus erythematosus (SLE), 119 SSc, 85 polymyositis/dermatomyositis (PM/DM)) in a rheumatology clinic were screened by radioimmunoprecipitation. Anti-RNAP III positive sera were also tested by immunofluorescence antinuclear antibodies and anti-RNAP III ELISA. Medical records of anti-RNAP III positive patients were reviewed.

Results

Among 21 anti-RNAP III positive patients, 16 met the American College of Rheumatology (ACR) SSc criteria at the initial visit but 5 did not; diagnoses were vasculitis, early polyarthritis, renal failure with RP, interstitial lung disease, and Sjögren's syndrome. The first two patients developed rapidly progressive diffuse SSc. An additional case presented with diffuse scleroderma without RP and RP developed two years later. Anti-RNAP III antibodies in these 6 cases of atypical clinical presentation were compared with those in 15 cases of typical (SSc with RP) cases. Anti-RNAP III levels by ELISA were lower in the former group (P = 0.04 by Mann-Whitney test) and 3 of 6 were negative versus only 1 of 15 negative in the latter (P < 0.05 by Fisher's exact test). Three cases of non-SSc anti-RNAP III positive patients had predominant reactivity with RNAP I with weak RNAP III reactivity and had a strong nucleolar staining. Three anti-RNAP III patients, who did not have RP at the initial visit, developed RP months later. Scleroderma developed prior to RP in 5 out of 16 (31%) in the anti-RNAP III group, but this was rare in patients with other autoantibodies. The interval between the onset of RP to scleroderma was short in anti-RNAP III positive patients.

Conclusions

Anti-RNAP III antibodies are highly specific for SSc; however, a subset of anti-RNAP III positive patients do not present as typical SSc. The interval between RP and scleroderma in this group is short, and 31% of patients developed scleroderma prior to RP in this group. Anti-RNAP III positive patients may not present as typical SSc and detecting anti-RNAP III may have predictive value.     

Anti-MJ/NXP-2 autoantibody specificity in a cohort of adult Italian patients with polymyositis/dermatomyositis

Introduction

Autoantibodies in patients with polymyositis/dermatomyositis (PM/DM) are associated with unique subsets, clinical course and outcome. Anti-MJ antibodies, which recognize the nuclear protein NXP-2/MORC3, are reported in ~25% of juvenile DM. Prevalence and clinical significance of anti-MJ antibodies in adult Italian PM/DM patients were studied.

Methods

Sera from 58 consecutive adult Italian PM/DM patients were analyzed by immunoprecipitation of ³⁵S-labeled K562 cells extract, ELISA (anti-MJ, Jo-1), Western blot and indirect immunofluorescence. Clinical associations were analyzed using information from medical charts.

Results

Anti-MJ antibodies were the most prevalent specificity (17%) found mainly in DM (30%, 8 cases) vs 8% of PM (2 cases, P = 0.02). Comparing 10 anti-MJ (+) vs 48 anti-MJ (-) cases, DM was more common (P = 0.03), and age at onset was younger in anti-MJ (+) (P = 0.0006). In anti-MJ (+), heliotrope rash (P = 0.01) and calcinosis (P = 0.09) were more frequent. None of them had heart or lung involvement, or malignancy. Myopathy in anti-MJ (+) patients responded well to therapy and none of them had elevated CPK at last visit (0% vs 25% in anti-MJ (-)). Only 60% of anti-MJ (+) showed immunofluorescent nuclear dots staining, despite PML localization of NXP-2/MORC3.

Conclusions

Anti-MJ antibodies are the most frequent specificity in our cohort of adult Italian PM/DM. Anti-MJ (+) were associated with young onset DM, calcinosis, no internal organ involvement and good response of myopathy to therapy. Anti-MJ reported in juvenile DM is also found in adult PM/DM, and could be a new useful biomarker.