Histopathological characterization of the naturally occurring hepatotropic virus infections of nude mice

In the last ten years the mutant athymic nude mouse has been used by many researchers as a model for studying pathological conditions in an immunodeficient host. A major problem with such mice is their susceptibility to viral infections indigenous to murine stocks, such as the hepatotropic mouse coronaviruses. In an effort to define the hepatotropic virus diseases indigenous to nude mice this paper details the pathogenesis and associated comparative histopathology of three common strains of mouse hepatitis virus, reovirus 3 and murine cytomegalovirus in the nude mouse.     

Antikörperbildung gegen Poliovirus-N- und -H-Antigen bei Immunisierung von Meerschweinchen

Zusammenfassung Sieben Gruppen von Meerschweinchen zu je 15 Tieren wurden mit virulenten und attenuierten StÄmmen von Poliomyelitis immunisiert und die Antikörperbildung gegen N- und H-Antigen beobachtet. In allen Gruppen wurden zuerst H-Antikörper und spÄter N-Antikörper gebildet. Im weiteren Verlauf der Immunisierung nimmt bei Typ I und Typ II die Bildung von N-Antikörpern wesentlich schneller zu, so da\ die N-Titer bald höher sind als die H-Titer. Gleichzeitig reagieren zuerst mehr Versuchstiere mit H-Antikörper-Bildung, wÄhrend spÄter mehr Tiere N-Antikörper bilden.Bei der Immunisierung mit Typ III reagieren mehr Tiere mit Antikörperbildung gegen H als gegen N, gleichzeitig sind die H-Titer wÄhrend des ganzen Verlaufs höher oder ebenso hoch wie die N-Titer. Die Antikörperbildung gegen die ImpfstÄmme entsprach weitgehend dem Verlauf bei den virulenten StÄmmen. Die Reaktion des Organismus auf die Zufuhr von N- und H-Antigen Ändert sich im Laufe der Immunisierung. Die zu einem spÄteren Zeitpunkt vorgenommenen Booster-Injektionen vermögen das initiale übergewicht der H-Antikörper nicht wiederherzustellen, selbst wenn mehr H- als N-Antigen zugeführt wird.

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Antibody production versus poliovirus N and H antigen after immunisation of guinea pigs

Summary Seven groups of guinea pigs consisting of 15 animals each were immunized with virulent and attenuated strains of poliomyelitis virus. Subsequently the antibody production versus N and H antigen was studied. The animals of all groups responded primarily by production of H antibodies and later by N antibodies. During the further course of immunization the production of N antibodies was much faster for type I and II, thus anti N titers soon were higher than anti H titers. In addition, more animals responded initially by production of H antibodies, while later on more animals produce N antibodies. During the immunization with type III more animals produced H than N antibodies and H titers were always higher than N titers or equal. Antibody production to vaccination strains corresponded to a far extent to that of virulent strains. Response of the organism changes during the course of immunization. Booster injections given at a later time do not recall the initial peak of H antibodies, even if a greater dose H antigen is given than N.

     

Cockroach allergen extract stimulates protease-activated receptor-2 (PAR-2) expressed in mouse lung fibroblast

Objective: To investigate whether cockroach allergen extract can stimulate Protease-activated receptor 2 (PAR-2) expressed in mouse lung fibroblast.Materials: We established an immortalized lung fibroblast cell line, DM5, from PAR-2 deficient mice. By stable transfection with either an empty vector (DM5/EV) or an expression vector encoding mouse PAR-2 cDNA (DM5/Par2), a pair of lung fibroblast cell lines with or without functional PAR-2 expression were prepared.Treatment: The cells were exposed to cockroach allergen extract {up to 800 protein nitrogen unit (PNU)/ml}, trypsin (up to 100 nM), SLIGRL agonist peptide (up to 500 M), and trans-cinnamoyl-LIGRO agonist peptide (up to 400 M).Methods: The cells were loaded with Fluo-3 calcium indicator and mobilization of intracellular calcium with the stimuli was monitored by a fluorometric plate reader. Extracellular signal-regulated kinase (ERK) phosphorylation was examined by Western blot analysis using an anti-phospho ERK antibody.Results: The cockroach extract induced intracellular calcium transients in a concentration dependent manner in DM5/Par2 but not in DM5/EV. The activity was abolished when the cockroach extract was heat denatured or pre-incubated with PMSF (phenylmethanesulfonyl fluoride) prior to the assay. Concomitantly, ERK phosphorylation was seen in DM5/Par2 with the cockroach extract but not with a heat-denatured extract. The responses were sensitive to an inositol-1,4,5 triphosphate antagonist (2-APB) indicating that calcium was mobilized from intracellular store.Conclusions: Cockroach allergen extract can activate PAR-2 and thereby stimulate mouse lung fibroblasts likely through protease(s). The present study proposes a potential mechanism for cockroach antigens, similar to house dust mite antigens, in the etiology of respiratory diseases.Received 29 February 2004; returned for revision 12 April 2004; accepted by M. Katori 22 April 2004     

Major histocompatibility complex class I molecules are required for the development of insulitis in non-obese diabetic mice

An early step in the development of autoimmune diabetes is lymphocyte infiltration into the islets of Langerhans of the pancreas, or insulitis. The infiltrate contains both CD4⁺ and CD8⁺ T cells and both are required for progression to diabetes in non-obese diabetic (NOD) mice. It has been thought that the CD4⁺ lymphocytes are the initiators of the disease, the islet invaders, while CD8⁺ cells are the effectors, the islet destroyers. We question this interpretation because NOD mice lacking MHC class I molecules, hence CD8⁺ T cells, do not display even insulitis when expected.     

The role of γδ T cells in priming macrophages to produce tumor necrosis factor-α

The secretion of tumor necrosis factor (TNF)-α from macrophages is regulated by both priming and triggering signals. We found that macrophages from mice lacking γδ T cells [T cell receptor (TCR) δ^?/- mice], which lack the gene encoding the δ chain, produced only small amounts of TNF-α in response to lipopolysaccharide (LPS) and showed a reduced level of expression of CD14. Pre-incubation of macrophages from TCR δ-/- mice with γδ T cells from their TCR δ^+/- littermates restored their capacity to produce TNF-α in response to LPS. The priming activity of γδ T cells was in part inhibited by neutralizing anti-interferon (IFN)-γ monoclonal antibodies. Collectively, these results suggest that γδ T cells play a role in priming macrophages to a steady state of activation via IFN-γ secretion, which allows them to produce TNF-α when exposed to LPS.     

Characterization of self-reactive T cells that evade tolerance in hepatitis B e antigen transgenic mice

Previous studies of hepatitis B e antigen (HBeAg)-expressing transgenic (Tg31e) mice have indicated that the degree of T cell tolerance was epitope specific. For example, T cells specific for residues 120–131 of HBeAg are profoundly tolerant, whereas a proportion of T cells specific for residues 129–140 escape tolerance induction in B10. S × B10-Tg31e mice. To understand the basis for differential tolerance towards two T cell sites on the same self antigen, we characterized T cell recognition of HBeAg by primary T cells and T cell hybridomas derived from HBeAg-Tg and non-Tg mice. The self-reactive T cells surviving in B10-Tg31e mice exhibited a unique fine specificity, albeit still focussed on HBeAg residues 129–140, which could be distinguished from the HBeAg-specific T cell repertoire in non-Tg B10 mice. Further, self-reactive T cells were comprised predominantly of Th2-type cells that preferentially evaded tolerance induction as compared to their Th1 counterparts. Because HBeAg may act as a tolerogen during the vertical transmission of chronic hepatitis B virus (HBV) infection, these results suggest that a predominance of HBeAg-specific Th2 cells expressing a limited repertoire may influence the initiation or the maintenance of the HBV chronic carrier state.     

Aqueductal lesions in 6-aminonicotinamide-treated suckling mice

Summary Suckling mice which received a single intraperitoneal injection of 6-aminonicotinamide on the 5th postnatal day, consistently developed hydrocephalus. During the early stages of hydrocephalus (7–9 days after injection), aqueductal lesions were characterized by edematous ependymal and subependymal cells, and spongy changes in the periaqueductal area, which resulted in aqueduct stenosis. Later stages (after 20 days post-injection) showed that these edematous changes totally subsided, leaving an obliterated aqueduct which was similar to that of human congenital hydrocephalus. At the completely obliterated area, ultrastructural investigation disclosed a normal-looking neuropil but no aqueductal lumen. In the remaining ependymal cell, increased intermediate filaments and lipid droplets occurred. These data suggest that acute ependymal cell degeneration during the perinatal period may result in the profile of aqueduct agenesis in human congenital hydrocephalus.Supported in part by research grants NS-03356, NS-10803 from NINCDS, USPHS     

In vitro H-serotonin (5-HT) synthesis and release in BALBc and C57BL mice. I. Terminal areas

"In vitro," 3H-5-HT and 3H-5-HIAA newly synthesized from 3H-TRP are measured in the caudate nucleus and the hippocampus of C57BL and BALBc mice. Higher synthesis, utilization and release are to be found in C57BL than in BALBc strain. In the hippocampus of C57BL this higher synthesis is due both to higher tryptophan hydroxylase activity and to higher tryptophan uptake ability. But in the caudate nucleus the initial accumulation of tryptophan is similar in both strains. Finally the two forms of monoamine oxidase (A and B) show also similar activities in both strain. These data will be compared to those obtained at the nerve cell body level in the paper (II).     

皮肤涂抹雌三醇对裸鼠甲状腺功能和肿瘤影响的效果观察

目的研究经皮涂抹外源性雌三醇(E₃)对裸鼠甲状腺功能及甲状腺移植瘤的影响。方法使用123只4周龄裸鼠,按体质量采用随机数字表法分为9组:①对照组、②低E₃组、③高E₃组、④乳头状甲状腺癌组(PTC组)、⑤乳头状甲状腺癌+高E₃组(PTC+高E₃组)、⑥滤泡状甲状腺癌组(FTC组)、⑦滤泡状甲状腺癌+高E₃组(FTC+高E₃组)、⑧未分化型甲状腺癌组(ATC组)和⑨未分化型甲状腺癌+高E₃组(ATC+高E₃组),均正常饮食饮水。除对照组、PTC组、FTC组和ATC组外,其余5组每日给予皮肤涂抹雌三醇乳膏,低E₃浓度为市售化妆品人均每日使用量中雌三醇含量的25倍、高剂量为100倍。40天后,收集各组裸鼠的24h尿样;尿碘采用砷铈催化分光光度法测定,尿E₃、血清E₃、血清甲状腺激素[游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺素(TSH)]和甲状腺抗体[甲状腺球蛋白抗体(TgAb)、甲状腺过氧化物酶抗体(TpoAb)],采用酶联免疫吸附实验[ELISA]测定。在接种肿瘤后的第4日起,每3 d测量肿瘤大小。结果①各组裸鼠血清E₃和尿E₃水平比较差异有统计学意义;其中FTC+高E₃组和ATC+高E₃组的血清E(310.22、14.18 pmol/L)和尿E(36.40、8.18 pmol/L)水平均分别显著低于FTC组和ATC组的血清E(326.52、22.80 pmol/L)和尿E(38.91、11.49 pmol/L)水平;而PTC+高E₃组仅血清E₃水平(12.17 pmol/L)显著低于PTC组(23.05 pmol/L);高E₃组的尿E₃水平显著低于低E₃组(6.92、8.94 pmol/L);低E₃组的尿E₃水平显著高于对照组(8.94、7.17 pmol/L),PTC组、FTC组和ATC组的血清E₃水平显著高于对照组和高E₃组(23.05、26.52、22.80比13.23、14.46 pmol/L)。②各组血清FT3水平比较差异没有统计学意义。各组血清FT4和TSH水平与对照组比较,差异均有统计学意义,其中各实验组的FT4水平均显著低于对照组,TSH水平均显著高于对照组,但PTC组与PTC组+高E₃组、FTC组与FTC+高E₃组、ATC组与ATC+高E₃组分别进行两两比较,FT4和TSH水平并差异无统计学意义。③各组裸鼠血清TgAb和TpoAb水平比较差异均有统计学意义。其中低E₃组、高E₃组、PTC+高E₃组、FTC组、ATC组和ATC+高E₃组的TgAb水平均显著高于对照组;各实验组的TpoAb水平均显著高于对照组。④各组裸鼠尿碘水平比较差异没有统计学意义。⑤各组裸鼠肿瘤体积大小比较差异均有统计学意义,PTC+高E₃组与PTC组比较,在接种肿瘤后的第7 d、16 d、25 d、28 d和37 d,肿瘤体积发生显著性差异(71.54、226.05、730.26、893.34、1242.12比49.87、325.50、551.28、664.38、967.78 mm³);FTC+高E₃组与FTC组比较,在接种肿瘤后的第25 d、28 d、37 d和40 d,肿瘤体积发生显著性差异(392.60、475.70、794.68、943.51比214.82、238.32、422.19、490.00 mm³);ATC+高E₃组与ATC组比较,在接种肿瘤后的第37 d和40 d,肿瘤体积发生显著性差异(217.53、432.10比577.19、1146.66 mm³)。结论外源性雌三醇能够诱导裸鼠发生甲状腺功能减退和抗体水平增高,同时对乳头状甲状腺癌和滤泡状甲状腺癌的生长有着促进作用,对未分化甲状腺癌的生长有抑制作用。     

Acceptability and Feasibility of a 13-Week Pilot Randomised Controlled Trial Testing the Effects of Incremental Doses of Beetroot Juice in Overweight and Obese Older Adults

Nitrate-rich food can increase nitric oxide production and improve vascular and brain functions. This study examines the feasibility of a randomised controlled trial (RCT) testing the effects of prolonged consumption of different doses of dietary nitrate (NO₃⁻) in the form of beetroot juice (BJ) in overweight and obese older participants. A single-blind, four-arm parallel pilot RCT was conducted in 62 overweight and obese (30.4 ± 4 kg/m²) older participants (mean ± standard deviation (SD), 66 ± 4 years). Participants were randomized to: (1) high-NO₃⁻ (HN: 2 × 70 mL BJ/day) (2) medium-NO₃⁻ (MN: 70 mL BJ/day), (3) low-NO₃⁻ (LN: 70 mL BJ on alternate days) or (4) Placebo (PL: 70 mL of NO₃⁻-depleted BJ on alternate days), for 13 weeks. Compliance was checked by a daily log of consumed BJ, NO₃⁻ intake, and by measuring NO₃⁻ and NO₂⁻ concentrations in plasma, saliva, and urine samples. Fifty participants completed the study. Self-reported compliance to the interventions was >90%. There were significant positive linear relationships between NO₃⁻ dose and the increase in plasma and urinary NO₃⁻ concentration (R² = 0.71, p < 0.001 and R² = 0.46 p < 0.001, respectively), but relationships between NO₃⁻ dose and changes in salivary NO₃⁻ and NO₂⁻ were non-linear (R² = 0.35, p = 0.002 and R² = 0.23, p = 0.007, respectively). The results confirm the feasibility of prolonged BJ supplementation in older overweight and obese adults.