Atrophy of compartments of rat lymph nodes related to an entry of lethally altered lymphocytes

Summary This paper reports the occurrence of an accumulation of lethally altered lymphocytes in the subcapsular sinus of a compartment or compartments of some lymph nodes, an unusual feature best developed in nodes of the mesenteric site in aging athymic animals. Many of these cells are rod-like. In other compartments, similar lymphocytes occurred at various depths in the nodal parenchyma. This was accompanied by the disappearance of a compartment's populations of normal lymphoid cells. The observations reveal that lymphocytes, altered in a tissue, may reach the subcapsular sinus of the draining node compartment and migrate into its parenchyma which then undergoes atrophy. The likely involvement of mast cells is discussed.This work was funded by the Medical Research Council of Canada.     

Characterization of dendritic cells,isolated from normal and stimulated lymph nodes of the rat

Summary Non-lymphoid dendritic cells were isolated from normal and paratyphoid vaccine-stimulated lymph nodes draining the rat skin. They were studied using enzymecytochemical, immunocytochemical and electron-microscopical methods. These cells had an irregular outline and an eccentrically situated nucleus. All showed acid phosphatase activity in a central area and expressed Ia antigen on the plasma membrane. Birbeck granules were exclusively present in dendritic cells isolated from lymph nodes in the induction phase of the immune response. This observation concurs with the presence of Birbeck granules in interdigitating cells in situ during the same period of the immune response. It is concluded that the dendritic cells are the in-vitro equivalents of the non-actively phagocytizing population of interdigitating cells.     

Mast cell types in the lymph nodes of the opossum Didelphis albiventris (Marsupialia,Didelphidae)

Summary Using histological and histochemical techniques, we have found a unique population of mast cells in the lymphatic sinuses of lymph nodes from different anatomical regions of the opossum. The lymphatic-sinus mast cells of the medullary sinuses were numerous, and could be easily distinguished from the connective-tissue mast cells of the dermis and lymph node capsule by their larger size and their enlarged cytoplasmic granules that were also more heterogeneous in shape and staining properties.     

Taenia crassiceps in the rat: transfer of immunity and immunocompetence with lymph node cells.

Using T. crassiceps infections of young AS₂ rats as a model system, it was shown that immunity can be transferred adoptively with lymph node cells, whereas serum from the same donors was ineffective. Normal adult rat lymph node cells also conferred immunocompetence on neonatal recipients. There was no correlation between antibody and elimination or persistence of metacestodes in infected rats. It is suggested that susceptibility of neonates to infection with this parasite is the result of functional immaturity of thymus-derived cells involved in cell-mediated immune responses rather than T-cell facilitation of antibody production.     

Morphological and functional characteristics of peritoneal mast cells from young rats

To study why neonatal and young rats are resistant to the effects of some secretagogues, such as compound 48/80 and 2.5-S nerve growth factor, we examined peritoneal mast cells from 14–15-day-old rats (young rats) and compared them to peritoneal mast cells from adults. Peritoneal mast cells from young rats contain approximately one-tenth of the amount of histamine observed in adult peritoneal mast cells. However, both cell populations contained similar low levels of the mucosal mast cell-associated protease rat mast cell protease II. Histochemical analysis of peritoneal mast cells from young rats using safranin O and berberine sulphate suggested that only a portion of the granules of these cells contained heparin. At an ultrastructural level the young rat peritoneal mast cell contains relatively few granules. The majority of mast cells from young rats have a bilobed or indented nucleus which is only rarely observed in adult cells. Functionally, the young rat peritoneal mast cell demonstrates a significantly reduced histamine release in response to the connective tissue mast cellspecific secretagogues compound 48/80 and 2.5-S nerve growth factor. In contrast, the percent histamine release in response to the neurotransmitter substance P, which degranulates both connective tissue mast cells and intestinal mucosal mast cells, was similar in the adult cells and the young rat cells. This study demonstrates substantial differences between the young rat and adult peritoneal mast cells which may explain the ability of very young animals to withstand large doses of certain secretagogues.     

Mast cells in rat dermis and jejunal lamina propria show a five-fold difference in unit granule volume

Summary The cytoplasmic granules of mast cells have a periodic multimodal size distribution in which the volumes of individual granules are integral multiples of the intermodal distance, a volume defined as the unit granule or ₁. In this study, we used two 3-month-old male rats to analyze two classical mast cell subpopulations, dermal connective tissue-type mast cells and jejunal lamina propria mucosal mast cells, for the morphometric characteristics of their cytoplasmic granules. Both and the mean volume of individual cytoplasmic granules were much smaller in dermal than in jejunal mast cells (ratios of 1:5.5 and 1:4.2, respectively), but dermal mast cells contained 150% more granules per cell than did jejunal mast cells. The two types of mast cells did not differ significantly in total cell volume, nucleus volume, aggregate volume of cytoplasmic granules per cell or numbers of unit granules comprising a granule of mean volume. These findings add unit granule volume to the list of phenotypic characteristics which express significant variation in anatomically distinct populations of mast cells.     

The passive transfer of protective immunity against Angiostrongylus cantonensis with immune lymph node cells from different lymphoid tissues in rats

-Yong W. K. and Dobson C. 1982. The passive transfer of proctective immunity against Angiostrongylus cantonensis with immune lymph node cells from different lymphoid tissues in rats. International Journal for Parasitology12: 423–425. Lymph node cells from the posterior cervical and mesenteric lymph nodes of immune rats passively protected syngeneic recipient rats against Angiostrongylus cantonensis better than cells from the spleen, thymic and inguinal lymph nodes either as reduced worms burdens and/or stunted growth. No antibody was detected in the sera of recipient rats after transfer of the cells and before infection which suggested that the protection was cell- rather than antibody-mediated.     

Effect of sizofiran on regional lymph nodes in patients with head and neck cancer

The immunomodulating effects of preoperative sizofiran (SPG) administration on regional lymph nodes were studied in patients with stage III or IV head and neck cancer, by comparing the immunofunction of peripheral blood. The regional lymph nodes were dissected surgically, and freshly obtained mononuclear cells were studied to investigate the interleukin-2 (IL-2) production, the LAK and NK activities, and the quantitative analysis of the surface phenotype of the mononuclear cells. The results indicated that SPG enhanced immunological activities in the regional lymph nodes, as shown by increased IL-2 production and cytotoxic activities of the effector cells (NK, LAK), and increased helper T lymphocytes (CD4⁺) in the tumor-uninvolved lymph nodes. The immunofunction following SPG administration was attenuated, but was still augmented in the regional lymph nodes with metastases. Therefore, SPG was found to be a biologic response modifier to enhance the immunofunctions of the regional lymph node in patients with head and neck cancer.     

Implantation of cultured thymic fragments in congenitally athymic (nude) rats

Summary Cultured thymic fragments correspond to the thymic microenvironment depleted of lymphocytes and dendritic cells. When these fragments are implanted under the kidney capsule of congenitally athymic rats, lymphocytes and dendritic cells of host origin enter the graft and induce thymus-dependent immunity in the recipient. This paper describes the ultrastructure of the fragments and the changes that occur during the restoration of normal thymic architecture. At the end of the culture period of 6–9 days and in the early stages after implantation, the grafts consist of keratin-containing epithelial cells of unusual morphology that can be labelled with antibodies raised against the epithelium of the mid/deep cortex and the subcapsule/medulla. Normal thymic architecture develops, including nerves and blood vessels, as lymphocytes populate the environment, and by 4–6 weeks the epithelial cells are the same phenotypically and ultrastructurally as those found in normal rat thymus. However, some areas without lymphocytes still contain the atypical epithelial cells seen before implantation. Large multinucleated giant cells are also present with a few associated epithelial cells of subcapsular/medullary phenotype. In conclusion, the cultured thymic fragments contain a hitherto unknown precursor epithelial cell with an atypical ultrastructure and phenotype that is not seen in normal development.     

Immunocytochemical and immuno-electron-microscopical study of growth hormone cells in male and female rats of various ages

Summary Growth hormone (GH) secretory cells were identified by immunogold cytochemistry, and were classified on the basis of the size of secretory granules. Type I cells contained large secretory granules (250\2-350 nm in diameter). Type II cells contained the large secretory granules and small secretory granules (100\2-150 nm in diameter). Type III cells contained the small secretory granules. The percentages of each GH cell type changed with aging in male and female rats of the Wistar/Tw strain. Type I cells predominated throughout development; the proportion of type I cell was highest at 6 months of age, and decreased thereafter. The proportion of type II and type III cells decreased from 1 month to 6 months of age, but then increased at 12 and 18 months of age. The pituitary content of GH was highest at 6 months of age, and decreased thereafter. Estrogen and androgen, which are known to affect GH secretion, caused changes in the proportion of each GH cell type. The results suggest that when GH secretion is more active the proportion of type I GH cell increased, and when GH secretion is less active the proportion of type II and type III cells increased. The type III GH cell may therefore be an immature type of GH cell, and the type I cell the mature type of GH cell. Type II cells may be intermediate between type I and III cells.     

Increased numbers of extra-adrenal chromaffin cells in the abdominal paraganglia of senescent F344 rats: A possible role for the glucocorticoid receptor

Summary The increase in numbers of extra-adrenal chromaffin cells of abdominal paraganglia in senescent F344 rats was investigated by 5-bromo-2-deoxyuridine immunocytochemistry. A monoclonal antibody raised against 5-bromo-2-deoxyuridine was used to react with tissue-sections of paraganglia taken from 28-month-old animals given weekly injections of the thymidine analog over a 14-week period. No immunoreactivity was detected in the extra-adrenal chromaffin cells, whereas control sections of intestinal epithelium showed abundant immunoreactivity. Also, the profile for immunoreactivity of the glucocorticoid receptor in relation to age was compared between extra-adrenal and adrenal chromaffin cells, which share cytological characteristics, but not the increase associated with senescence. In the extra-adrenal chromaffin cells, the intensity of receptor immunostaining was unchanged, while in the adrenal chromaffin cells it decreased with age. These results indicate that hypertrophy of the paraganglia in aged F344 rats is not due to the proliferation of extra-adrenal chromaffin cells. Instead, they suggest that the chromaffin cell phenotype may be induced in pre-existing cells and that the expression of the glucocorticoid receptor has an intrinsic role in this change.     

Synthesis of platelet-derived growth factor by cells of splenic red pulp in normal rats

A population of cells in the spleens of normal rats was found to contain platelet-derived growth factor (PDGF) B chain mRNA. These cells were found predominantly in the red pulp and nuclear morphology of some was consistent with that of macrophages. Similar cells were also shown by immunocytochemical staining to contain PDGF-AB/BB. These PDGF-positive cells were also found almost exclusively in the red pulp. It has been suggested by others that PDGF plays an important role in the function of the lymphohemopoietic microenvironment.     

Intraoperative evaluation of sentinel lymph nodes in breast cancer: comparison of frozen sections,imprint cytology and immunocytochemistry

M. Francz, K. Egervari and Z. Szollosi
Intraoperative evaluation of sentinel lymph nodes in breast cancer: comparison of frozen sections, imprint cytology and immunocytochemistry Objective: We analysed the utility of imprint cytology with rapid immunocytochemistry and frozen section analysis for the evaluation of sentinel lymph nodes in breast cancer patients. Methods: The sensitivity, specificity, and positive and negative predictive values have been calculated for each method individually, each pair and all three together. We compared these results with those of routinely processed paraffin sections. Results: The sensitivity and specificity of each of the three methods for detection of metastatic carcinoma were as follows: 69.4% and 97.8% for touch imprint cytology; 58.3% and 100% for frozen sections; 68.5% and 98.9% for rapid immunocytochemistry. When the methods were combined, the highest accuracy was achieved by touch imprint cytology, frozen sections, touch imprint cytology plus rapid immunocytochemistry, or touch imprint cytology frozen section analysis and rapid immunocytochemistry, each of these having identical sensitivity and specificity of 72.2% and 97.8%, respectively. Conclusions: In our study the combined accuracy of the three methods was the same as combining touch imprint cytology and frozen sections or touch imprint cytology plus rapid immunocytochemistry. Rapid immunocytochemistry provides an additional parameter and preserves tissue for permanent sections.     

Characterization of obestatin- and ghrelin-producing cells in the gastrointestinal tract and pancreas of rats: an immunohistochemical and electron-microscopic study

Both ghrelin and obestatin are derived from preproghrelin by post-translational processing. We have morphologically characterized the cells that produce obestatin and ghrelin in new-born and adult Sprague-Dawley rats that were freely fed, fasted, or subjected to gastric bypass surgery or reserpine treatment. Tissue samples collected from the gastrointestinal tract and pancreas were examined by double-immunofluorescence staining, immunoelectron microscopy, and conventional electron microscopy. Obestatin was present in the stomach, duodenum, jejunum, colon, and pancreas. In the stomach, differences were noted in the development of obestatin- and preproghrelin-immunreactive (IR) cells on the one hand and ghrelin-IR cells on the other, particularly 2 weeks after birth. Preproghrelin- and obestatin-IR cells were more numerous than ghrelin-IR cells in the stomach, suggesting the lack of ghrelin in some A-like cells. Most obestatin-producing cells in the stomach were distributed in the basal part of the oxyntic mucosa; these cells co-localized with chromogranin A (pancreastatin) and vesicle monoamine transporters type 1 and 2, but not with serotonin or histidine decarboxylase. Immunoelectron microscopy revealed the obestatin- and ghrelin-producing cells to be A-like cells, characterized by numerous highly electron-dense granules containing ghrelin and obestatin. Some granules exhibited an even electron density with thin electron-lucent halos, suggestive of monoamines. Feeding status, gastric bypass surgery, and reserpine treatment had no obvious effect on the A-like cells. In the pancreas, obestatin was present in the peripheral part of the islets, with a distribution distinct from that of glucagon-producing A cells, insulin-producing beta cells, and cells producing pancreatic polypeptide Y. Thus, obestatin and ghrelin co-localize with an anticipated monoamine in A-like cells in the stomach, and obestatin is found in pancreatic islets. This study was supported by a grant from the Cancer Foundation of St. Olav’s Hospital, Trondheim, Norway.     

Formation of contacts between mast cells and sympathetic neurons in vitro

Summary Functional interactions between mast cells and peripheral nerves may occur at sites of association seen in vivo. To study the interactions, we developed a tissue culture model of murine sympathetic neurons co-cultured with rat basophilic leukaemia (RBL-2H3) cells (homologues of mucosal mast cells) or rat peritoneal mast cells. In co-cultures of up to 3 days, light microscopy identified neurite contacts with peritoneal mast cells or RBL-2H3 cells, but not with glial cells or fibroblasts. Electron microscopy confirmed membrane-membrane contact between neurites and RBL-2H3 cells. Time-lapse analysis of interactions between neurons and RBL-2H3 cells showed that 60–100% of the cells in a given field acquired neurite contact within 17 h. In matching control studies, there was no increase in the frequency of neurite contact with cells of the rat plasmacytoma line (YB2/0): these were not selected as targets, and contacts were broken if formed. Time-lapse records of the derivation of neurites from their path suggested a neurotropic effect of mast cells, with neurite contact ensuing when the intervening distance was less than 36±4 m. Once formed, contacts were invariably maintained throughout the period of examination (up to 72 h), in contrast to YB2/0 or fibroblast contacts. We conclude that neurons selectively form and maintain connections with cells representative of rat connective tissue-type and mucosal mast cells in vitro. Similar interactions in vivo could promote nerve/mast cell contacts, which may allow bidirectional communication between the nervous and immune systems.     

Stereological and functional investigations on isolated adrenocortical cells: Zona fasciculata/reticularis cells of chronically ACTH-treated rats

Summary The morphology and function of isolated inner (zona fasciculata/reticularis) adrenocortical cells of rats pretreated with ACTH for 3, 6, 9 or 12 days were investigated. ACTH treatment induced a notable time-dependent enhancement in the steroidogenic capacity (corticosterone production) and growth of inner cells. The volumes of cells, mitochondrial compartment, membrane space [the cellular space occupied by smooth endoplasmic reticulum (SER) membranes] and lipid-droplet compartment, as well as the surface area of mitochondrial cristae and SER tubules, were increased in relation to the duration of ACTH pretreatment, and showed a highly significant positive linear correlation with both basal and stimulated corticosterone production. The acute exposure of isolated cells to ACTH provoked a striking lipid-droplet depletion, the extent of which was linearly and positively correlated with stimulated corticosterone secretion. The hypertrophy of the mitochondrial compartment and SER are interpreted as the morphological counterpart of the enhanced steroidogenic capacity of inner adrenocortical cells, inasmuch as the enzymes of steroid synthesis are located in these two organelles, and it is well known that chronic ACTH exposure stimulates the de novo synthesis of many of them in vivo. The rise in the number of lipid droplets, in which cholesterol is stored, is interpreted as being due to the fact that, under chronic ACTH treatment, the processes leading to cholesterol accumulation in adrenocortical cells (exogenous uptake and endogenous synthesis) exceed those of its utilization in basal steroid secretion. Cholesterol accumulated in lipid droplets as a reserve material may be rapidly utilized after acute ACTH exposure to meet the needs of the enhanced steroidogenic capacity of adrenocortical cells.     

Ultrastructure and morphometry of testicular Leydig cells and the interstitial components correlated with testosterone in aging rats

The ultrastructure of testicular interstitium in young and aged adult rats was analysed using morphometric methods, and the plasma testosterone concentration was measured. With increasing age there was an augumentation in the volume of collagen fibrils in the intercellular matrix and in blood vessels. During the aging process (approximately two years) the average volume of the Leydig cell decreased from 1364 m³ to 637 m³, but the number of Leydig cells in paired testes increased from 53x10⁶ to 113x10⁶. The absolute volume of smooth surfaced endoplasmic reticulum (SER) per Leydig cell amounted in aged rats to 78% of that in young adult rats. The total amount of SER in paired testes increased by 62% with aging. The present analysis suggests that the ability of SER to maintain peripheral testosterone concentration decreases with age. In young adult rats the absolute volume of peroxisomes per Leydig cell correlated significantly with the concentration of testosterone in blood and also with the absolute volume of SER per Leydig cell. These results combined with ultrastructural observations of close apposition of peroxisomes and SER suggest that peroxisomes have a role in testosterone secretion by Leydig cells.Visiting scientist to Laboratory of Electron Microscopy (Director: Prof. L.J. Pelliniemi)     

Expression profiles of interferon‐stimulated gene 15 and prostaglandin synthases in the ovine lymph nodes during early pregnancy

Lymph nodes are distributed all over the body and are part of the lymphatic system. The interferon‐stimulated gene 15 kDa protein (ISG15) and prostaglandins (PGs) are involved in the establishment of pregnancy and are expressed in the uterus during early pregnancy in sheep. In this study, the ovine lymph nodes were obtained on Day 16 of the estrous cycle, and Days 13, 16, and 25 of pregnancy, and the expression of ISG15 and PG synthases, including cyclooxygenase 1 (COX‐1), COX‐2, prostaglandin E (PGE) synthase (PTGES), and a PGF synthase (aldo‐keto reductase family 1, member B1, AKR1B1) were detected by quantitative real‐time polymerase chain reaction, western blot analysis, and immunohistochemistry analysis. Our results showed that there were peaks in the expression of mRNAs and the proteins of ISG15, COX‐1, COX‐2, PTGES, and AKR1B1 in the lymph nodes during early pregnancy and that the COX‐2 and AKR1B1 proteins were limited to the subcapsular sinus and lymph sinuses. In conclusion, the ISG15, COX‐1, COX‐2, PTGES, and AKR1B1 were upregulated in the maternal lymph nodes, which may be beneficial for the development of conceptus, maternal systemic immunoregulation, and anti‐luteolysis during early pregnancy in sheep.     

Postnatal changes in the distribution and elemental composition of Paneth cells in normal and corticosteroid-treated rats

Summary Paneth cells containing zinc-rich granules were found in the small intestine of 6-day-old rats. These cells were more numerous in older animals and were consistently most common in the distal ileum. The zinc content of granules from 10-day-old rats was similar to that found in adults (ca 300 mg atoms/kg dry weight) but no calcium could be detected. An injection of cortisone acetate at 5 days resulted in a premature increase in the numbers of Paneth cells in 10-day-old rats. The cell granules contained normal, adult levels of zinc, a calcium concentration of ca 400 mg atoms/kg dry weight and also an increased concentration of phosphorus.     

Purinergic signaling in inflammatory cells: P2 receptor expression, functional effects, and modulation of inflammatory responses

Extracellular ATP and related nucleotides promote a wide range of pathophysiological responses via activation of cell surface purinergic P2 receptors. Almost every cell type expresses P2 receptors and/or exhibit regulated release of ATP. In this review, we focus on the purinergic receptor distribution in inflammatory cells and their implication in diverse immune responses by providing an overview of the current knowledge in the literature related to purinergic signaling in neutrophils, macrophages, dendritic cells, lymphocytes, eosinophils, and mast cells. The pathophysiological role of purinergic signaling in these cells include among others calcium mobilization, actin polymerization, chemotaxis, release of mediators, cell maturation, cytotoxicity, and cell death. We finally discuss the therapeutic potential of P2 receptor subtype selective drugs in inflammatory conditions.