The mast cell reaction to a staphylococcal infection occurring against a background of immunodeficiency after cyclophosphane administration

Materials on the study of the morphofunctional state of mast cells in mouse in experimental staphylococcal infection under the conditions of cyclophosphamide-induced immunodeficiency are presented. As revealed in this study, the infectious process developing in the presence of immunodeficiency is accompanied by the profound and prolonged suppression of the morphofunctional status of mast cells and natural immunity factors at the peak of the disease.     

Assessment of th- quantity of mast cells in the organs of the gastrointestinal tract of rats and frogs]

A method of evaluation of mast cell concentration in which all the tissues of an organ are included gives statistically significant figures. This method showed mast cell concentration in the digestive tract organs of rats and frogs to be a fixed value within a morphofunctional zone. In the tongue the mast cell concentration was the same both along its length and in the symmetrical parts of the organ. The concentration of mast cells diminished considerably from the tongue, the duodenum and down to the stomach.     

Changes in mast cells after their exposure to constant electromagnetic field

By means of luminescent histochemistry effect of a constant magnetic field with induction 60 mTl (exposition for 2, 6, 36 h and 7 days) has been studied in order to reveal contents of catecholamines in mesenteric mast cells and in the intestinal mesentery cells in 50 white Wistar rats. In 2-6 h specific luminescence of the mast cells increases, however, at prolongation of the exposure up to 30 h metabolism of catecholamines in the mast cells is inhibited noticeably++ (luminescence disappears). In 8 days amount of the mast cells and specific luminescence of catecholamines decrease. The essential shifts revealed in the system of the mast cells of the mammalian should be taken into consideration in the magnetic-therapeutic practice. Close spatial relations between the mast cells and the mesenteric adrenergic terminals have been elucidated, demonstrating their morphofunctional interconnection.     

The effect of different methods of isolating thrombocytes on the surface structure and biochemical parameters of the serotonin system of these cells]

The method of platelets' isolation influences their morphofunctional state. The study of the surface structure of platelets with the method of scanning electron microscopy shows, that the nonactivated form of platelets is characterized for the cells, isolated by gel filtration, but platelets which are isolated by centrifugation are activated. Platelets' activation under centrifugation is shown to connect with the changes of biochemical parameters of platelet serotonin system: the increase of the velocity of the 3H-serotonin reuptake and of the 3H-imipramine specific binding.     

Stereological analysis of thyroid mast cells in rats after exposure to extremely low frequency electromagnetic field and the following "off" field period

Influence of extremely low frequency electromagnetic field (ELF-EMF) on thyroid gland mast cells was investigated on male Mill Hill rats. Animals were exposed to EMF (50 Hz, 50 microT to 500 microT, 10 V/m) from 24 hours after birth, 7 hours/day, 5 days/week for three months when a part of animals (group I) was sacrificed, while the rest of them were subjected to recovery evaluation and sacrificed after one (group II), two (group II) and three (group IV) weeks following the exposure. Stereological analysis on toluidine blue-stained paraffin sections showed increased volume density of degranulated mast cells in all groups and, except in group III, and numerical density as well, implicating the sensitivity of thyroidal mast cells to power frequency EMFs. Since in our previous investigations, morphofunctional alterations of thyroid gland in rats exposed to ELF-EMF were found the contribution of released mast cell mediators to these changes could be presumed.     

Stimuli from conspecifics influence brain mast cell population in male rats

It is well established that mast cells occur within the brain of many species, and that the brain mast cell population is not static, but changes with the behavioral and physiological state of the animal. In this study, we tested whether exposure to conspecifics alters the number of brain mast cells in male rats, and then investigated the nature of stimuli influencing the changes observed in the number and localization of brain mast cells. Five days of cohabitation with an ovariectomized, estrogen-progesterone (OVX + EP)-treated female resulted in the largest number of thalamic mast cells, while pairing with such a female physically separated by a wire mesh or with a novel male produced a smaller, but significant increase over other pairings (OVX females for 5 days, OVX and OVX + EP females for 1 day, familiar or isolated males for 5 days). In all groups, mast cells were localized within specific dorsal thalamic nuclei, including the paraventricular nucleus, anterior nuclear group, or mediodorsal, ventroposterior, or medial geniculate nuclei. The results suggest that the behavioral and/or endocrine factors associated with cohabitation with conspecifics are sufficient to alter the number of brain mast cell-specific nuclei in the thalami of male rats and thus can provide targeted delivery of neuromodulators to specific regions of the brain that process information concerning the normal physiological state of the animal.     

Mast cells in the rat brain synthesize gonadotropin-releasing hormone

Mast cells occur in the brain and their number changes with reproductive status. While it has been suggested that brain mast cells contain the mammalian hypothalamic form of gonadotropin-releasing hormone (GnRH-I), it is not known whether mast cells synthesize GnRH-I de novo. In the present study, mast cells in the rat thalamus were immunoreactive to antisera generated against GnRH-I and the GnRH-I associated peptide (GAP); mast cell identity was confirmed by the presence of heparin, a molecule specific to mast cells, or serotonin. To test whether mast cells synthesize GnRH-I mRNA, in situ hybridization was performed using a GnRH-I cRNA probe, and the signal was identified as being within mast cells by the binding of avidin to heparin. GnRH-I mRNA was also found, using RT-PCR, in mast cells isolated from the peritoneal cavity. Given the function of GnRH-I in the regulation of reproduction, changes in the population of brain GnRH-I mast cells were investigated. While housing males with sexually receptive females for 2 h or 5 days resulted in a significant increase in the number of brain mast cells, the proportion of mast cells positive for GnRH-I was similar to that in males housed with a familiar male. These findings represent the first report showing that mast cells synthesize GnRH-I and that the mast cell increase seen in a reproductive context is the result of a parallel increase in GnRH-I positive and non-GnRH-I positive mast cells.     

Immunofluorescence studies indicate that the basic trypsin-kallikrein-inhibitor of bovine organs (Trasylol) originates from mast cells.

Using the indirect immunofluorescence technique, the basic kallikrein-trypsin inhibitor of bovine organs, Trasylol, could be localized in tissue mast cells of bovine lung, liver, pancreas and parotid gland. Identification of cells exhibiting specific fluorescence as tissue mast cells was achieved by combined light and electron microscopic diagnosis of bovine liver tissue sections. The presence of Trasylol in mast cells explains the widespread distribution of this inhibitor in functionally totally different organs or tissues of the bovine organism, as determined earlier by biochemical means. Identification of Trasylol as a mast cell constituent will facilitate the search for the biological function of this inhibitory protein in connection with a unique and highly specialized cell population.     

Dynamics of microcirculatory system recovery in the post-stress period

Twenty-four-hour immobilization or electric stimulation for 6 h were used in rats as stressors. The first stressor caused more profound and protracted disturbances in the microcirculatory system. The recovery of the microcirculation occurred in 50% of animals by day 6 and in 100% by day 14 after immobilization. The terminal blood flow recovery after 6-hour electric stimulation was seen in a day. Vascular permeability after 24-hour immobilization returned to normal in 24 h, and after 6 h of electric stimulation in 6 h. This process correlated with the morphofunctional status of mast cells and was probably phasic in nature.     

New possibilities of studying microbial objects by laser interference microscopy

A novel method, laser interference microscopy, has been developed for studying the morphofunctional state of bacterial cells and the structure of bacterial communities. The following potentialities of the method are shown: rapid determination of the cell structure and subcellular structures (nucleus zone, vacuoles, lamellar structures) and the physiological state of the cell, as well as the study of the structure of bacterial communities (biofilm). The method does not require any additional preparation of cells before the investigation (fixation, staining, treatment with contrasting substances), which reduces the possible appearance of artifacts to a minimum and enables one to use laser interference microscopy for in vivo investigations.     

Mast cells in the rat brain synthesize gonadotropin‐releasing hormone

Mast cells occur in the brain and their number changes with reproductive status. While it has been suggested that brain mast cells contain the mammalian hypothalamic form of gonadotropin‐releasing hormone (GnRH‐I), it is not known whether mast cells synthesize GnRH‐I de novo. In the present study, mast cells in the rat thalamus were immunoreactive to antisera generated against GnRH‐I and the GnRH‐I associated peptide (GAP); mast cell identity was confirmed by the presence of heparin, a molecule specific to mast cells, or serotonin. To test whether mast cells synthesize GnRH‐I mRNA, in situ hybridization was performed using a GnRH‐I cRNA probe, and the signal was identified as being within mast cells by the binding of avidin to heparin. GnRH‐I mRNA was also found, using RT‐PCR, in mast cells isolated from the peritoneal cavity. Given the function of GnRH‐I in the regulation of reproduction, changes in the population of brain GnRH‐I mast cells were investigated. While housing males with sexually receptive females for 2 h or 5 days resulted in a significant increase in the number of brain mast cells, the proportion of mast cells positive for GnRH‐I was similar to that in males housed with a familiar male. These findings represent the first report showing that mast cells synthesize GnRH‐I and that the mast cell increase seen in a reproductive context is the result of a parallel increase in GnRH‐I positive and non‐GnRH‐I positive mast cells. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 113–124, 2003     

The morphofunctional characteristics of the cecum in experimental escherichiosis]

Using the model of experimental escherichiosis in mice by means of morphological, immunomorphological, morphometrical and electron microscopy methods, the authors give morphofunctional characteristics of caecum 15 minutes to 2 weeks after inoculation. The authors show the dynamics of infectious process, characterized by changes of microcirculation, increasing lymphoplasmocellular infiltration, dystrophic changes in cells of neuroplexes and degranulation of mast and endocrine cells. The data obtained show that pathological process in caecum during experimental escherichiosis has an immune character, that the above portion of the intestine is a part of endocrine system.     

Presence of a blastocyst and mast cell depletion of the mouse uterus

The mast cell population has been studied during early decidualization of the mouse uterus. The number increases in early pregnancy until the attachment phase when a sharp depletion is noticed. This fall has been correlated with stimuli of maternal origin, but at the same time the presence of a blastocyst at the presumptive implantation sites seems to exert a significant effect on the depletion of mast cells. A relationship between the number of mast cells in the uterus and the physiological state of the organ has definitely been established [Harvey, 1964; Likar and Likar, 1964; Gibbons and Chang, 1972; Brandon and Evans, 1983]. The number of mast cells in the pregnant uterus is known to decrease around the time of implantation in the rat [Shelesnyak, 1960; De Feo, 1967; Brandon and Bibby, 1979]. Several workers believe that the mast cell population and histamine content decrease as a result of a rise in circulating estrogen [Westin, 1955; Gibbons and Chang, 1972; Spaziani, 1975]. In the present communication the possibility of a relationship between the decrease in mast cell population and the presence of a blastocyst, whose estrogenic role has been reported [Dickmann and Dey, 1973; Dickmann et al., 1975; Sengupta et al., 1977], in the uterine horn has been discussed.     

Effect of non-fractionated and low-molecular heparin on the functional state of mast cells]

The state of the mast-cell population of rats treated with unfractionated and low-molecular weight heparins under stress conditions has been comparatively studied by the morphometrical assay. The stress was produced by 60 min immobilization followed by intravenous injection of unfractionated (UF) or low-molecular weight (LMW) heparin. The stress-induced heparin release from mast cells resulted in a 3.3-fold decrease of the index of saturation with heparin and in a significant increase of granulolysis and degranulation. The mast cell secretory status reached the preinjection level within 20 min in rats with UF heparin injected (15 unit/200 g). At the same time mast cells of rats with LMW heparin have no such ability. The data obtained indicate that LMW heparin in contrast to UF heparin cannot be accumulated (or accumulated very slowly) by mast cells. This fact as well as low affinity of LMW heparin to endothelium and blood platelets promote its preservation in blood for a long time.     

Effect of sub-diaphragmatic vagotomy on gastric mucosal mast cell population in pylorus ligated rats.

Gastric mucosal mast cell population was studied following sub-diaphragmatic vagotomy in albino rats, 6 and 12 h after pylorus ligation. Sub-diaphragmatic vagotomy significantly increased the gastric mucosal mast cell population in both 6 and 12 h groups, the increase being more in the latter. The results suggest that the vagal impulses act on the gastric mucosal mast cells causing their degranulation. Following vagotomy the contents stay bound within the mast cells. Increase in mast cell population with the longer experimental situation was possibly due to the continuation of normal turnover of the mast cells in the gastric mucosa. The present study, however, does not lead to a conclusion that the vagal influence on mast cell population is similar throughout the gastro-intestinal tract.     

Quantitation of mast cell heparin by flow cytofluorometry.

Mast cells can be automatically identified in a mixed cell population by flow cytofluorometry after Berberine sulphate staining. Volume specific counts of the total number of cells and number of mast cells, as well as frequency distributions of fluorescence intensities of mast cells, based on a large number of cells, can be rapidly obtained. Results obtained by microscope fluorometry of cells identified by phase contrast microscopy showviously published results it may be inferred that the fluorescence intensity of individual mast cells is proportional to mast cell heparin content. The automated cell counts correlated very well with manual hemocytometer counts. Both cell counts and the determination of mean mast cell fluorescence showed excellent reproducibility.     

Histochemical and Morphological Characteristics of Canine Cardiac Mast Cells

Cardiac mast cells have been recently isolated and characterized in humans, however canine cardiac mast cells have not been investigated. The objective of this study is to describe the histological and morphological characteristics of canine cardiac mast cells and examine the potential usefulness of canine models in investigating the role of mast cells in cardiovascular pathology. Canine cardiac mast cells could be easily identified by staining with Toluidine Blue or FITC-avidin. Using Toluidine Blue staining, we demonstrated fewer mast cells in formalin-fixed samples than in specimens fixed in Carnoy's, thus identifying a formalin-sensitive mast cell population in the canine heart. Mast cells were equally distributed in atria and ventricles with approximately 50% showing a perivascular location. Using enzyme-histochemical techniques, we detected tryptase and chymase activity in canine cardiac mast cells. Ultrastructural studies identified mast cells as granular cells with an eccentric non-segmented nucleus. Immunohistochemistry with the macrophage specific antibody AM-3K demonstrated that resident cardiac macrophages were 1.9 times more numerous than mast cells, also showing a predominantly perivascular (60%) location. Perivascular macrophages were more often periarteriolar, whereas perivascular mast cells were more often located along small veins and capillaries. Due to their ability to release cytokines and growth factors and their strategic perivascular location, resident cardiac inflammatory cells, such as mast cells and macrophages, may be important in pathological processes causing myocardial inflammation and fibrosis. Furthermore, mast cell-derived chymase, an important angiotensin II-forming enzyme may have a significant role in regulating the cardiac renin-angiotensin system.     

Generation and characterization of alpha-chymase-Cre transgenic mice

The Cre-loxP technology allows the introduction of somatic gene alterations in a tissue and/or cell type specific manner. The development of transgenes that target Cre expression to specific cell types is a critical component in this system. Here, we describe the generation and characterization of transgenic mouse lines expressing Cre recombinase under the control of the baboon alpha-chymase promoter, designated Chm:Cre, in order to direct Cre expression specifically to mouse mast cells. Chm:Cre expression was detected in mast cells in lung and colon tissue. Cre-mediated recombination in these mice identified a population of mature tissue resident mast cells using ROSA26R reporter mice. No Cre-expression and Cre-mediated recombination was induced in in vitro generated bone marrow derived mast cells or mast cells isolated from the peritoneal cavity indicating that Cre-expression under the control of the alpha-chymase promoter is solely activated in tissue resident mast cells. These Chm:Cre transgenic mice represent a useful tool to specifically inactivate genes of interest in mast cells of these tissues.     

Heparin secretion by mast cells as an index of the status of the anticoagulant system

The status of the mast cell population was studied and compared after administration of trypsin or alpha-thrombin in similar molar concentrations. Morphometry disclosed a substantial shift of the mast cell population towards light, heparin-free cells within one minute after alpha-thrombin administration. The index of mast cell saturation with heparin dropped below 1. The maximal heparin secretion was observed at the 5th minute of experiment. The morphometric criteria of the mast cell population returned to basal level in 120 minutes. These data along with a significant increase in the level of complex heparin compounds and plasma thrombin time indicate heparin release as a result of the effector action of the anticoagulation system. No changes were observed in the activity of complex heparin compounds and in thrombin time after intravenous injection of trypsin. It is suggested that high heparin secretion by mast cells may serve as criterion of the active status of the anticoagulation system.     

Studies of the multifaceted mast cell response to bacteria

The concept of mast cells as playing a critical and multifaceted role in immune defense against pathogens is new, and effective ways to study and validate this notion are required. Recently, a number of approaches have been described that can be used to study the molecular aspects of mast cell recognition of pathogens, and of specific mast cell responses, such as mediator release, bacterial endocytosis and mast cell migration, to pathogens.