Immunosuppressive effect of restraint stress on the initiation of allergic rhinitis in mice

BACKGROUND: Exposure to acute stressors modulates both innate and acquired immune function. However, little is known about whether stress has the potential to modulate the pathogenesis of allergic rhinitis. OBJECTIVES: To determine the effects of acute restraint stress on the initiation of allergic rhinitis in a murine model. METHODS: CBA/J mice were repeatedly intranasally sensitized with phospholipase A2 (PLA2) from honeybee venom without adjuvant. Restraint stress was applied using uniform cylinders once a week for a continuous 8-hour period, on five occasions in total. Production of PLA2-specific antibodies and degree of nasal and blood eosinophilia were compared between stressed and control mice. RESULTS: Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE and marked eosinophilia in both the nose and blood in CBA/J mice. Exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a. Conversely, the stress exerted no significant effect on eosinophilia. CONCLUSIONS: Exposure to acute restraint stress inhibits antigen-specific antibody production, but not local or systemic eosinophilia. The results of this study suggest that acute stress has the potential to modulate the initiation of allergic rhinitis.     

Different immunosuppresive effects of anti-red blood cell sera and their fractions obtained from various animal species

Sheep red cells (RC) were coupled with HSA by means of an HSA—anti-SRBC IgG conjugate. The coupled RC were used to prepare rosettes with spleen cells of mice immunized to HSA in Freund's complete adjuvant. The rosettes were fractionated on discontinuous Ficoll gradients and the rosette-rich and rosette-poor fractions were tested for ability to transfer adoptively secondary responsiveness to HSA. Efficiency of transfer was measured in terms of haemagglutination titres. Memory of HSA was shown to be associated with rosette-forming cells, i.e. with cells carrying receptors for HSA. Several parameters of the adoptive transfer system employed were studied. The HSA-coupled RC proved to be very efficient in stimulating secondary responses to HSA. High titres of haemagglutinating antibodies (up to 1/80,000) were obtained with 10 × 10⁶ spleen cells transferred and 2 × 10⁶ spleen cells consistently gave titres of the order of 1/10,000.     

CD44 stimulation down-regulates Fas expression and Fas-mediated apoptosis of lung cancer cells

Cytotoxic T lymphocytes (CTL) play a major role in the rejection of tumor cells, but tumor rejection does not always occur in vivo, indicating that defects in anti-tumor immune responses may be common. We here document a novel function for CD44--using lung cancer cells, we showed that stimulation of CD44 reduced Fas expression and Fas-mediated apoptosis: (i) lung cancer cells expressed high levels of CD44; (ii) engagement of CD44 on the cells by a specific antibody or fragmented hyaluronan reduced Fas expression; (iii) CD44 cross-linking reduced Fas-mediated apoptosis; (iv) stimulation of CD44 on lung cancer cells decreased IFN-gamma production by autologous CTL; and (v) CD44 stimulation prevented killing of lung cancer cells by autologous CTL. Based on these findings, we postulate a new concept--that interaction of CD44 on lung cancer cells with fragments of extracellular hyaluronan present in the surrounding extracellular matrix reduces Fas expression as well as Fas-mediated apoptosis of cancer cells. This leads to reduced susceptibility of the cells to CTL-mediated cytotoxicity through the Fas-Fas ligand pathway.     

Histochemical studies on glycosaminoglycans in Bruch's membrane of postnatal rat eyes

Localization of glycosaminoglycans (GAG) in Bruch's membrane of postnatal rat eyeballs was examined histochemically. Fixed eyeballs from postnatal rats (ages 5 days and 8 weeks) were routinely processed and embedded in paraffin wax or Quetol 651 resin. Paraffin-embedded tissue sections were stained with hematoxylin and eosin or sensitized high iron diamine procedure in combination with selective methods such as GAG-degrading enzyme digestions and/or a chemical modification, and examined by light microscopy. Quetol 651-embedded ultrathin sections were stained with heavy metals and examined by electron microscopy. In rats at postnatal day 5, Bruch's membrane contained mainly chondroitin sulfate (CS) and heparan sulfate (HS). In contrast, at 8 weeks after birth the membrane included a large amount of dermatan sulfate (DS) and HS. According to electron microscopic findings, Bruch's membrane on day 5 consisted of only 3 layers without a central elastic layer. However, at 8 weeks after birth the membrane was constructed of 5 layers. These findings suggested that the difference in GAG molecular species in the membranes at 5 days and at 8 weeks after birth could be correlated with the development and maturation of the collagenous layer in Bruch's membrane. Moreover, maturation of Bruch's membrane may contributes to the architectural stabilization of the outer portions of the photoreceptor cells.     

X-linked mixed deafness (DFN3): cloning and characterization of the critical region allows the identification of novel microdeletions

We have found that the microsatellite marker AFM207zg5 (DXS995)maps to all previously described deletions which are associatedwith X-linked mixed deafness (DFN3) with or without choroideremiaand mental retardation. Employing this marker and pHU16 (DXS26)we have identified two partially overlapping yeast artificialchromosome clones which were used to construct a complete 850kb cosmid contig. Cosmids from this contig have been testedby Southern blot analysis on DNA from 16 unrelated males withX-linked deafness. Two novel microdeletions were detected inpatients which exhibit the characteristic DFN3 phenotype. Bothdeletions are completely contained within one of the known DFN3-deletions,but one of them does not overlap with two previously describeddeletions in patients with contiguous gene syndromes consistingof DFN3, chorolderemia, and mental retardation. Assuming thatonly a single gene is involved, this suggests that the DFN3gene spans a chromosomal region of at least 400 kb.     

Stereological analysis of Reinke's crystals in human Leydig cells

Summary Reinke's crystals in human Leydig cells were analyzed stereologically to assess their functional role. Testicular tissues were taken from seven older men (57–82 years old) with prostatic carcinoma and also from seven younger men (26–38 y.o.) complaining of male infertility. Sections 0.5 m thick, stained with toluidine blue or Heidenhein's iron-hematoxylin were examined by a point-counting method and with a Particle Measurement Computor System (MC). When the patients were grouped by age, the mean crystal volume, the number of crystals per cell, the volume of crystals per cell and the volume ratio of crystals to cell were significantly larger in the older age group than in the younger age group. In particular, the latter three variables correlated well with the age of subjects, with correlation coefficients of r=0.66–0.85. On the other hand, none of these variables had any correlation with the concentration of plasma testosterone. These results indicate that Reinke's crystals can be considered as degenerative products in cell life but not as facultative constituents for testosterone production.Supported in part by a grant from Medical Foundation of Ehime, Japan     

Stoichiometric salt-linkage formation of trimethylammonium glycol chitosan iodide with a carboxylic type ion exchanger

The adsorption of trimethylammonium glycol chitosan iodide (TGCI) on Dowex CCR-2 resin was investigated at different pH values and resin weights. The concentration of Na⁺ or Ca²⁺ ions, released by the ion exchange reaction with TGCI, was measured by inductively coupled plasma spectroscopy. It was found that the amount of the released ions is comparable to that of the absorbed TGCI. This indicates that the salt-linkage formation of carboxylate ions of the exchanger with ⊕N(CH₃)₃-groups in TGCI follows a stoichiometric relationship. This result is discussed in connection with the form of the polymer layer adsorbed on the solid surface.     

Suppressive effects of receptive field surround on neuronal activity in the cat primary visual cortex

Effects of sinusoidal grating stimulus presented outside the classical receptive field (CRF) on neuronal responses were studied in the primary visual cortex of anaesthetized cats. Among 101 cells electrophysiologically recorded, the predominant effect of the stimulus in the receptive field surround (SRF) was the suppression of responses to the CRF stimulation, and the SRF grating suppressed them up to 56% of the responses (44% suppression) to the CRF stimulus alone. The strong suppression was observed more often in layer II/III cells than in other layers and in complex cells more often than in simple cells. The modulatory effects by SRF stimulus might be enhanced by the cortical recurrent excitation particularly in the superficial layers. We also examined whether the modulation by the surround grating exhibits a differential effect according to the presence or absence of figure-ground segregation in the stimulus configuration. For this purpose, effects of stimulus configuration with orientation-, direction-contrast or relative spatial phase difference between CRF and SRF stimuli (figure-ground segregated configuration) were compared with those of uniform configuration of stimulus (non-segregated configuration). There was a population of cells, which exhibited significantly stronger suppression with non-segregated configuration than with figure-ground segregated configuration. Such differential modulation of response by the SRF stimulus in the primary visual cortex is a possible basis of perceptual figure-ground segregation.     

The corrosion resistance of pure titanium in organic acids

The purpose of this study was to assess the corrosive properties of titanium at various pH values. Cast pure titanium specimens were immersed in 128 mmol/l of lactic and formic acids at pH 1.0-8.5 for 3 weeks at 37 degrees C. The solubility, color, weight and chemical binding state of specimens were observed. Titanium dissolved in all lactic acid. The amount of dissolved titanium tended to decrease with a higher pH. In formic acid, the amount of dissolved titanium at pH 1.0 was larger than that in lactic acid at the same pH, but less than the detectable limit at pH 4.0 or higher. Significant discoloration was macroscopically observed only in formic acid at pH 2.5 and 4.0. The weight of the titanium samples immersed in lactic acid all decreased, but it was not affected by pH. In formic acid, the weight decreased at pH 1.0 and increased at pH 2.5-5.5. Thickening of the TiO2 corresponding to that showing discoloration was observed in the superficial oxide film of the titanium samples. Our results show that the corrosive properties of titanium are markedly dependent on pH in formic acid, and relatively less dependent on pH in lactic acid in which titanium is dissolvable at pH 1.0-8.5.