Mucosal FOXP3-expressing CD4+ CD25high regulatory T cells in Helicobacter pylori-infected patients

Helicobacter pylori chronically colonizes the stomach and duodenum and causes peptic ulcers or gastric adenocarcinoma in 10 to 20% of infected individuals. We hypothesize that the inability of patients to clear H. pylori infections is a consequence of active suppression of the immune response. Here we show that H. pylori-infected individuals have increased frequencies of CD4(+) CD25(high) T cells in both the stomach and duodenal mucosa compared to uninfected controls. These cells have the phenotype of regulatory T cells, as they express FOXP3, a key gene for the development and function of regulatory T cells, as well as high levels of the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) protein. In contrast, mucosal CD4(+) CD25(low) and CD4(+) CD25(-) cells express little FOXP3 mRNA and low levels of the CTLA-4 protein. Mucosal CD4(+) CD25(high) T cells are present in individuals with asymptomatic H. pylori infections as well as in duodenal ulcer patients. The frequencies of CD4(+) CD25(high) cells are also increased in the stomachs of H. pylori-infected patients with gastric adenocarcinoma, particularly in cancer-affected tissues. These findings suggest that regulatory T cells may suppress mucosal immune responses and thereby contribute to the persistence of H. pylori infections.     

Changes in the surface electromyogram during increasing isometric shoulder forward flexions

Summary When using electromyographic techniques in the evaluation of muscular load it is necessary to determine the mathematical relationship between the torque and the amplitude of the electromyographic signal. Isometric gradually increasing contractions up to 100% MVC can then be used. Often more than linear increases for the amplitude (RMS) — force regression have been reported. The present study was designed to test whether changes in power spectral density function take place during a gradually increasing isometric contraction (duration 10 s). Twenty-two clinically healthy females performed an increasing isometric shoulder forward flexion for 10 s using an isokinetic dynamometer. Electromyographic activity was measured in trapezius, deltoid, infraspinatus and biceps brachii using surface electrodes. Mean torque values were determined together with mean power frequency (MPF) and root mean square values (RMS) from the EMG signals for each 256 ms period. The RMS-torque regressions showed higher regression coefficients during the 6th to 9th sec than during the first 5 s. No significant correlation existed between MPF for the four muscles and the torque. A gradual decrease in MPF was generally found from the 6th s. It is concluded that this decrease in power spectral density function might have contributed to the significantly higher regression coefficient for the RMS torque regression at the high output part of the gradually increasing isometric contraction.     

Localization of interleukin-13 gene-expressing cells in tuberculin reactions and lesional skin from patients with atopic dermatitis

Interleukin (IL)-13 is a cytokine thought to play an important role in IgE-mediated allergic reactions. The aims of the present study were to localize IL-13 mRNA in positive tuberculin reactions and atopic dermatitis lesions using in situ hybridization and to study the possible influence of atopy on the cytokine gene expression in tuberculin reactions. Punch biopsy specimens were taken from tuberculin reactions in 17 nonatopic and 12 atopic (Phadiatop positive), but otherwise healthy, individuals 72h after injection of purified protein derivative, from chronic lichenified lesions and nonlesional skin in six patients with atopic dermatitis and from normal skin in 12 healthy individuals. IL-13-mRNA-producing cells were located mainly in the dermal-cell infiltrates, both in atopic dermatitis lesions and tuberculin reactions. In the atopic dermatitis lesions, IL-13-mRNA expression was found in close apposition to the epidermis. Higher numbers of IL-13-mRNA-producing cells were observed in the dermal-cell infiltrates of chronic lichenified skin lesions of patients with atopic dermatitis (13.3 cells/mm2, range 0.6-42.4 cells/mm2) than in the tuberculin reactions (1.1 cells/mm2, range 0-3.8 cells/mm2) (P<0.01) despite the larger cell infiltrates in the tuberculin reactions. No significant difference in IL-13 or interferon-gamma gene expression in the tuberculin reactions was seen between atopic and nonatopic individuals.     

Temporal expression and cellular origin of CC chemokine receptors CCR1, CCR2 and CCR5 in the central nervous system: insight into mechanisms of MOG-induced EAE

Background  

The CC chemokine receptors CCR1, CCR2 and CCR5 are critical for the recruitment of mononuclear phagocytes to the central nervous system (CNS) in multiple sclerosis (MS) and other neuroinflammatory diseases. Mononuclear phagocytes are effector cells capable of phagocytosing myelin and damaging axons. In this study, we characterize the regional, temporal and cellular expression of CCR1, CCR2 and CCR5 mRNA in the spinal cord of rats with myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE). While resembling human MS, this animal model allows unique access to CNS-tissue from various time-points of relapsing neuroinflammation and from various lesional stages: early active, late active, and inactive completely demyelinated lesions.     

Fluid balance and arterial blood pressure during intracarotid infusions of atrial natriuretic peptide (ANP) in water-deprived goats

The aim of this study was to investigate if atrial natriuretic peptide (ANP) plays a role in the control of water balance in goats and whether ANP affects the increase in mean arterial blood pressure (MAP) which accompanies drinking in water-deprived animals. Bilateral intracarotid infusions were made in female adult goats deprived of water for 48 h. ANP (1.5 micrograms min-1, n = 5, or 4.75 micrograms min-1, n = 5) was infused for 40 min. In control experiments isotonic saline (n = 7) was infused. The goats got access to water 35 min after the start of the infusions. During saline infusions they drank 2.9 +/- 0.4 litres, during the low dose of ANP 1.9 +/- 0.6 litres (n.s. vs saline), and during the high dose of ANP 0.6 +/- 0.2 litres (P less than 0.01 vs saline). Plasma vasopressin concentration did not change during saline infusions until after drinking, when it decreased. The vasopressin concentration increased in one goat after infusion of the low dose of ANP and in two goats after the high dose of ANP. The low dose of ANP caused no change in MAP in four goats, but MAP dropped in the one in which vasopressin concentration increased. MAP fell in all goats infused with the high dose (P less than 0.01), with the largest changes occurring in animals showing increased vasopressin concentration. During the act of drinking a temporary increase of MAP was observed when saline or the low dose of ANP was infused, but this response was attenuated during infusions of the high dose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interference of Salivary immunoglobulin A antibodies and other salivary fractions with adherence of Streptococcus mutans to hydroxyapatite.

The adherence of Streptococcus mutans to hydroxyapatite was studied in the presence of salivary fractions with varying activity of naturally occurring immunoglobulin A (IgA) antibodies. Human parotid saliva from different donors was fractionated by chromatography and compared. Salivary IgA antibodies had no decisive effect on the adherence of the S. mutans strain used. High-molecular-weight salivary components from some subjects had an adherence-promoting effect, whereas fractions collected after the void volume of a Sepharose 2B column always inhibited adherence. The data indicate that the influence of unfractionated saliva on adherence is dependent on the net effect of adherence-promoting and adherence-inhibiting components. This principle has to be considered when the effect of human saliva on microbial adherence is studied.     

The majority of human CD3 epitopes are conferred by the epsilon chain

Transgenic mouse T cells expressing the human CD3 chain bindthe majority (29/36) of monoclonal antibodies (mAbs) specificfor human CD3. A proportion of these mAbs are also able to recognizeisolated CD3 in a soluble, recombinant form. Thus, CD3 can confermost CD3 epitopes on the TCR-CD3 complex, but many determinantsmay require assembly of the complex for their formation. A numberot mAbs did not recognize -transgenic T cells and probably needother CD3 subunits for binding. CD3-specific mAbs from eachof the three groups defined here, as well as mAbs directed againstthe TCRß heterodimer, are all able to activate T cells.Therefore mAb attachment at several different sites on the TCR-CD3complex can give rise to activation signals. This suggests thatthe cross-linking function of mitogenic antibodies may be theirmost significant property, rather than the perturbation of aparticular ‘functional epitope’.     

Early influx of horseradish peroxidase into axons of the hypoglossal nerve during Wallerian degeneration.

Horseradish peroxidase (HRP) was applied around mouse hypoglossal nerves which were damaged by a crush or a ligature. HRP was then visualized distal to the lesions by light- and electron microscopic histochemistry. At the injury the enzyme entered axons and could also be detected several millimetres down in the distal segment. By 24 h reaction product (r.p.) was either diffusely distributed in the axoplasm or present in various vesicular organelles. Our results indicate that there is a rapid influx of macromolecules into axons after a lesion to a nerve. A similar uptake of 'wound substances' into axons distal to an injury might well have some relation to the process by which axonal breakdown is initiated during Wallerian degeneration.