Mast cell mediators excite the afferents of cat small intestine

The influence of intra-arterial injections of 5-hydroxytryptamine, histamine and prostaglandin E2 on afferent impulse activity of mesenteric nerves of small intestine was studied. In anaesthetized cats 5-hydroxytryptamine (10(-5)-10(-4) M) and histamine (10(-5)-10(-3) M) were shown to increase the impulse activity in a dose-dependent manner. Metergolin, 5-hydroxytryptamine antagonist, suppressed the effect of 5-hydroxytryptamine. Clemastine and cimetidine, antagonists of H1 and H2 histamine receptors respectively, distinctly diminished excitatory histamine effects. Prostaglandin E2 (10-30 micrograms/kg) enhanced the afferent impulse activity. The results suggest that afferents of the small intestine may be involved in reception of inflammatory and immune responses.

Changes in afferent impulse activity of small intestine mesenteric nerves in response to antigen challenge

Sprague-Dawley rats (weight 130-150 g) were sensitized by an intraperitoneal injection of 1 mg chicken egg albumin with 0.25 ml Freund's adjuvant to stimulate immunoglobulin E antibody production. Leukocyte migration inhibitory factor was used as an indicator of animal sensitization. In acute electrophysiological experiments on sensitized animals, an intra-arterial or intraluminal chicken egg albumin (100 microg) challenge evoked a 10% enhancement of the activity of mesenteric nerves of the small intestine, regardless of the injection site chosen. Afferent nerve activity in control animals was not changed during the chicken egg albumin challenge. Morphometry at the light microscope level showed activation of mast cell degranulation after the antigen challenge to presensitized rats. Intraluminal injections of a stimulator of mast cell degranulation, compound 48/80 (20-30 mg), were found to increase afferent discharges in intact rats. An antagonist of H1 histamine receptors, clemastine, reduced the effect of compound 48/80. The results obtained provide direct evidence for the stimulation of sensory nerve endings by mast cell mediators released during mast cell degranulation.

Mechanism of Activation of Enteric Nociceptive Neurons via Interaction of TLR4 and TRPV1 Receptors

Evidence obtained by immunohistochemical double labeling and confocal laser scanning microscopy suggests that capsaicin, a ligand of the TRPV1 nociceptive vanilloid receptor, increases the number of TLR4-positive neurons in the rat colon myenteric plexus. In colitis caused by trinitrobenzene sulfonate, an increase in TRPV1 expression was more significant in both plexuses. Specific inhibitor of the TLR4 (C34) pattern-recognition receptor reduces TRPV1 expression in enteric neurons of both intact rats and rats with induced acute colitis. Thus, stimulation of nociceptive neurons by means of direct activation of their receptors of innate immunity (TLR4) is one of the possible mechanisms underlying the visceral pain in bacterial invasion and inflammatory bowel diseases.

[Allergic bronchopulmonary aspergillosis in patients with asthma: Results of a prospective study]

AIM

To estimate the frequency of fungal sensitization and the incidence of allergic bronchopulmonary aspergillosis (ABPA) in asthmatic patients.

SUBJECTS AND METHODS

A total of 140 asthmatic patients were examined. They underwent allergologic (skin tests for fungal allergens, estimation of total and fungal allergen-specific IgE levels) and mycological (microscopy and inoculation of respiratory biosubstrates) examinations. Chest computed tomography, when indicated, was done. A group of patients with ABPA and that of patients with severe asthma and fungal sensitization were identified.

RESULTS

The frequency of fungal sensitization in asthmatic patients was 36%; the main allergenic fungi were Aspergillus and Alternaria. The incidence of ABPA was as high as 4% in the patients with asthma and 11% in those with severe asthma and fungal sensitization.

CONCLUSION

The given current diagnostic criteria will assist practitioners to identify ABPA, to prevent its progression, and to initiate specific anti-inflammatory and antifungal therapy in due time.

[Common variable immunodeficiency in adults]

The paper analyzes 7 cases of common variable immune deficiency (CVID), a primary immunodeficiency disease. All the cases were detected in outpatients over the age of 40 years. The diagnosis was based on their history data and general clinical findings with due regard for the results of previously conducted functional studies, expert opinions, and the results of immunological studies including the quantitative and functional indices of T and B cells, phagocytes and the levels of immunoglobulins. The analysis showed that the early signs of impaired immunity in all the patients were seen by physicians of various specialties in both outpatient and inpatient settings. Generalizing of all information about the patient could become the basis for a simple and accessible practical public-health study of immunoglobulins levels significantly sooner than this diagnosis being verified. This testifies that the physicians of various specialties are partially aware of the clinical signs of immunodeficiency states and that there is a need for a clinical immunologist in adult healthcare facilities. This is especially important since the early clinical manifestations of both primary immunodeficiency disorders that are increasingly frequently detected and nonhereditary - secondary ones can be very similar. The timely verification of the diagnosis is necessary for prescribing adequate therapy with intravenous immunoglobulins to prevent severe chronic pyoinflammatory lung disease and disability in patients with CVID.

[The effect of the mast-cell mediators histamine and prostaglandins on the afferent nerve fibers of the small intestine in the cat]

Histamine was shown to increase afferent impulse activity of the small intestine's mesenteric nerves in a dose-dependent manner, the effect being reduced by antagonists of the H1 and H2 histamine receptors. PG E2 and PC D2 also enhanced the afferent impulse activity. Interaction of antigens with the intestinal mast cells seems to participate in immune response.

[Changes in pulmonary ventilation after shafts in acid-base equilibrium in the skeletal muscles of the cat]

In anesthetized cats, perfusion of the m. gastrocnemius with solutions simulating metabolic acidosis produces a reflex enhancement of breathing proportional to the acidosis degree. Perfusion with solutions having pH 7.0, 6.8 and 6.3 induced 4.6 +/- 1.0, 6.3 +/- 0.5 and 10.3 +/- 1.2% increases of the minute volume of ventilation, resp. These increases were mainly due to increases of the tidal volume rather than of respiratory rate. An increase of the mean blood pressure also occurred whereas heart rate did not change significantly. Hindlimb perfusion experiments revealed that reflex changes of the blood pressure and breathing depended on the muscle mass perfused. Possible participation of the muscle receptors sensitive to changes of metabolism in exercise hyperpnea, is discussed.

[Cost benefit of detection and treatment patients with tuberculosis in Ivanovo region, Russian Federation]

To execute the tuberculosis control programme in the Ivanovo Region, the authors calculated the cost of detection of a tuberculosis case at patients' referrals to a therapeutical-and-prophylactic institution for medical aid and during prophylactic X-ray fluographic examinations and the cost of tuberculosis cure while treating the patient at a hospital in the intensive treatment phase (2-3 months) and in the outpatient setting or at a day hospital by the intermittent method in the continued treatment phase. The costs calculated were compared with those obtained by early approaches. The cost of detection of a tuberculosis case was 1580.8 for referrals in 1996 and 4000 for X-ray fluographic prophylactic examinations. The costs of hospital tuberculosis cure (85% cure rates) only in the intensive treatment phase (for 2-3 months) and outpatient intermittent treatment (for 2-4 months) with and without meals were 2415.34 and 2142.17 respectively. If the efficiency is equal, the introduction of new approaches to organizing the detection and treatment tuberculosis cases may save 3877.7 for each cured tuberculosis case and 2419.2 for each patient detected.

[The localization of neurons innervating the upper portion of the duodenum in the dorsal motor nucleus of the vagus nerve]

In anesthetized cats, using method of the retrograde transport of the horseradish peroxidase and electrophysiological techniques, the dorsal motor nucleus neurons innervating upper portion of the duodenum were found. Maximal number of such neurons were found within 1.0 to 2.5 mm rostral to the obex. The effects of the neurons stimulation on the electrical activity of the duodenum smooth muscles were studied. Possible role of the dorsal motor nucleus neurons in realisation of gastro-duodenum motor reflexes is discussed.

[Tissue chemoreceptors]

Intraarterial administration of acids or perfusion with solutions inducing acidosis in the small intestine tissue, increase the afferent impulsation in the splanchnic nerves as well as the arterial pressure in anesthetized cats. Threshold concentrations of lactic and carbonic acids don't exceed, at that, their normal contents in the blood and tissues. Similar data were obtained in perfusion of the small intestine with blood of a donor animal whose acid--alkaline balance (AAB) was altered. The tissue receptors were found to be more sensitive to the metabolic rather than respiratory acidosis, due to different alteration of of the intratissue pH. Sensitivity of the skeletal muscles' chemoreceptors proved somewhat lower as compared with the small intestine receptors. Nevertheless, the threshold shifts of the AAB parameters in the m. gastrocnemius perfusion developed within the normal range. The changes of minute volume of ventilation revealed the possibility of tissue receptors participation in the reflex control of respiration as well. The data on adequate sensitivity of the tissue receptors to terminal products of aerobic and anaerobic metabolism: carbonic and lactic acids, once more corroborate V. N. Tchernigosky's ideas of the tissue chemoreceptors as a special class of receptor structures providing the c.n.s. with necessary information on intensity of the tissue metabolism.

[The role of visceral receptors in the mechanisms of neuroimmune interactions in mammalian small intestine]

Exogenous administration of mast cell degranulation products into blood as well as their endogenous release induced by compound 48/80 or repeated egg albumin administration to sensitized rats proved to increase activity of mesenteric afferent nerve fibers in the small intestine. In addition, the primary contact with a foreign protein triggered a cascade of chemical processes mobilizing antioxidant systems and increasing nitric oxide production in the small intestinal tissues. Interleukin-1beta or Escherichia coli lipopolysaccharide injections also had a long-term stimulating effect on intestinal receptors. Indometacin inhibited the effects induced by the bacterial endotoxin and interleukin-1beta. The obtained data suggest that small intestinal interoceptors can monitor chemical environment and modulate body's responses to foreign antigens. Interleukins-1beta acts as a signal transmitter between immune cells and interoceptors, which is mediated by the production of secondary signal substances, in particular, prostaglandin-2 and histamine.

[The localization of neurons in the nodose ganglion of the cat that innervate the rostral portion of the duodenum]

The method of axonal transport of horseradish peroxidase was used for studying the sites of localization and morphological features of sensory neurons of the vagus nerve in the left and right ganglion nodosum innervating the rostral part of the duodenum. Animals under nembutal narcosis were given 90-100 mcl of 33% solution of horseradish peroxidase ("Olaine", Riga RZ 2.7) injected into a limited area (1 x 1 sm) of the muscular layer of the duodenum. Horseradish peroxidase labelled neurons were found bilaterally in the both ganglia. The number of neurons in the left ganglion was 91 +/- 23, in the right one--115 +/- 24. The sensory cells are mainly of the ellipsoid form and of different sizes. Areas of sections of the neurons vary from 100 to 1300 mkm2, most on them having the area from 300 to 700 mkm2. The distribution of neurons according to the sizes of their areas have no substantial differences in the left and right ganglia. It was found that 65% of neurons in the right ganglion and 67% in the left one are localized in its caudal half.

THE INFLUENCE OF MICROMYCETES ASPERGILLUS FUMIGATUS ON IMMUNE RESPONSE REGULATION IN PATIENTS WITH ASTHMA

Aspergillus fumigatus is able not only to sensitize patients with atopy, but also to colonize the respiratory tract, remaining a constant source of allergens due to the small size of the spores and thermal tolerance. Sensitization to A.fumigatus in patients with asthma is associated with a severe course of the disease, and the proliferation of fungal spores in the respiratory tract can lead to the development of allergic bronchopulmonary aspergillosis (ABPA). Currently, the role of micromycetes in the immunopathogenesis of asthma has not been sufficiently studied. The objective was to evaluate the features of the immune response regulation in patients with ABPA or asthma with sensitization to A.fumigatus. The study included 15 patients with ABPA, 10 patients with asthma with sensitization to A. fumigatus, 16 patients with asthma without sensitization to A. fumigatus. The control group consisted of 16 conditionally healthy volunteers. All patients underwent a clinical and functional examination. The Asthma Control Test questionnaire was used to assess disease control. The diagnosis of asthma was established in accordance with the recommendations of the GINA working group (Global Initiative for Asthma, updated, 2022), the diagnosis of fungal sensitization and ABPA in accordance with the recommendations of the ISHAM working group (International Society for Human and Animal Mycology, 2013). The subpopulations of blood lymphocytes were determined by flow cytometry. The A.fumigatus allergen was added to peripheral blood samples to evaluate the production of IFN, IL-10 and IL-13. The levels of cytokines in cell culture supernatants, as well as total IgE, specific IgE (sIgE) to A. fumigatus and thymus and activation-regulated chemokine (TARC) in blood serum were determined by enzyme immunoassay. Significantly higher levels of total IgE, sIgE to A. fumigatus and TARC in blood serum were found in patients with ABPA and asthma with sensitization to A. fumigatus compared to patients with asthma without sensitization to A. fumigatus. The results of immunophenotyping of lymphocytes revealed a significant excess of Th2 memory cells and T-regulatory cells in all patients with asthma compared to the control group. The number of Tfh2 was higher but Th17.1 memory cells were lower in patients with sensitization to A. fumigatus compared to those of conditionally healthy volunteers. Patients with ABPA had significantly higher number of Th2 memory cells and TARC content compared to patients with asthma with sensitization to A. fumigatus. The increased activity of Th2 memory cells is confirmed by increased secretion of IL-13 and IL-10 following decrease in IFN production in response to specific stimulation of blood cells by the fungal allergen compared to the patients with asthma and the control group. A positive correlation was revealed between the number of Th2 memory cells and the levels of sIgE, IgE, TARC, a negative correlation with FEV1. Thus, contact with A. fumigatus significantly enhances the activity of Th2 memory cells in patients with asthma which can lead to a severe course of the disease and the formation of allergic bronchopulmonary aspergillosis. The identified features of the immune response dictate the need for a personalized approach to the choice of therapeutic tactics in this category of patients.

[The morphological characteristics of the parasympathetic innervation of the pyloric sphincter in the cat]

The method of axonal transport of horse-radish peroxidase was used to detect the localization of neurons in the dorsal motor nucleus of the vagus nerve sending the axons to the pyloric sphincter. The investigation was carried out in cats. Under study were also morphological features of the nodular ganglion responsible for afferent innervation of the sphincter. The maximum amount of the corresponding cells are found in the dorsomedial part of the dorsal motor nucleus in the area from +1.0 to +2.0 mm (with respect to obex). The afferent neurons to which information comes from interoceptors of the sphincter zone along the vagus nerve fibers, are distributed in the left and right nodular ganglia almost evenly. The major part of these cells have the area of 300-800 mkm2.

[The effect of serotonin on the receptors of the cat small intestine]

5-HT was shown to increase dose-dependently the afferent activity in the cat mesenteric nerves. Metergolin suppressed the effects of serotonin. The data obtained suggest that the small intestine afferents may take part in reception of immune response.

Localization of neurons innervating the upper portion of the duodenum in the motor nucleus of the vagus nerve

Using the method of the retrograde axonal transport of horseradish peroxidase and a microelectrode technique, a population of neurons sending axons to the upper portion of the duodenum was identified in the dorsal motor nucleus of the vagus nerve. It was established that the maximal number of such neurons was located 1.0-2.5 mm rostral to the obex. The effects of their stimulation on the electrical activity of the smooth muscles of the duodenum was studied.

[Possible role of muscle receptors in regulating arterial pressure during shifts in acid-base balance in muscles]

It has been shown on anesthetized cats that perfusion of the gastrocnemius muscle with a solution simulating metabolic acidosis (pH 7.1, [HCO3-]-12.7 mM, PCO2- 38 mmHg) produces a threshold reflex increase in the arterial blood pressure. The relationship between the magnitude of the pressor reflexes and the decreased bicarbonate concentration and pH is depicted by a curve that consists of two areas: an initial progressive rise of the blood pressure is replaced after pH 6.6 by a more abrupt increase in the intensity of the pressor reflexes. The results indicate that the muscle receptors may take part in arterial blood pressure regulation during acid-base changes in the skeletal muscle.