The immune system and age

Basing on numerous facts, obtained during last years at investigation of the immune system organs, a definite idea has been formed on peculiarities of their structure during certain stages of human ontogenesis. The immune organs appear early in embryogenesis and by birth they have reached their morphological maturation. This is evident as formation of diffuse lymphoid tissue in lymphoid noduli, that can have germinative centers, where young cells of the lymphoid line are formed. The immune system organs develop especially quickly after birth during first years of the postnatal ontogenesis. The peak in development of the organs of immunogenesis, amount and size of the lymphoid noduli occurs during the childhood and adolescent age. Each immune organ has its peculiarities that are determined by their place in the organism, value and intensity of antigenic effect. Beginning from the adolescence and youth amount of the lymphoid tissue and lymphoid noduli in the organs decreases, in their place connective and adipose tissue grows out.     

The anatomy and topography of the lymphoid formations of the human stomach in postnatal ontogeny]

By means of macro-microscopical methods 80 stomachs from persons of various age have been studied. In the mucous membrane of the human stomach during all age periods of postnatal development the lymphoid tissue is present as diffusely scattered lymphocytes, their microaccumulations and lymphoid noduli. Maximal amount of the lymphoid noduli is observed during the second mature age. The greatest number of the lymphoid noduli per 1 cm2 of the mucous membrane surface is revealed in the area of the lesser curvature and in the pyloric part of the stomach. Most often the lymphoid noduli are situated in the depth of the lumen proper of the mucous membrane, somewhat more seldom--in its more superficial parts, in the muscular lamina and in the submucous tela. The lymphoid noduli with germinative centers are met beginning from the first childhood up to old age. The greatest amount of diffusively scattered lymphocytes is situated near the lymphoid noduli and in the deep layer of the lamina proper of the mucous membrane.     

Morphology of mesenteric lymph nodes after balneologic procedures

Strong and weak sulfate baths produce certain increase in amount and in area of the lymphoid noduli with the germinative center, in the deep cortex and a decrease in the relative area of the medullary substance, while iodobromine baths facilitate to an outgrowth of the medullary cords and to ectasia of sinus lumens. After the balneoprocedures lymphoid noduli appear in the deep cortex; amount of destructive cells in the medullary sinuses, in the medullary cords and in the intermedullary zone decreases; amount of mast cells, eosinophiles and neutrophiles increases (slightly). Blast transformation of small lymphocytes and increase in number of middle lymphocytes are observed in the germinative centers.     

Structural and functional characteristics of the lower tracheobronchial lymph nodes in the rat after administration of dimethyl sulfate

By means of microanatomical methods the inferior tracheobronchial lymph nodes in 36 Wistar rats have been investigated, when the animals have been subjected to the effect of dimethylsulfate (DMS) vapors. The effect of the substance in doses 0.1 and 2.0 mg/m3 for 2 and 14 days has been studied. Comparison of relative parameters of the structural components areas and the cytological profile of the lymph nodes has been performed. DMS effects for 2 and 14 days in the maximal tolerance concentration (MTC) results in increasing area of the connective tissue stroma and the cortical substance, in comparison with the control, as well as in decreasing area of the medulla substance. At the contact with DMS for 2 days (at a corresponding MTC) certain changes of the nodular cytological profile are noted. They demonstrate that to the given time of the experiment the adaptive processes in the lymph nodes have no time to develop completely. DMS effect for 14 days in the same concentration produces an increased destruction of cellular elements and inhibits the plasmocellular reaction intensity (in comparison to the control and the experiment for 2 days). DMS maximal concentration (2.0 mg/m3) results in decreasing area of the lymphoid noduli with germinative centers. Intensity of mitotic processes decreases and autoimmune processes develop.     

Structure of the small-intestinal lymphoid patches in albino rats at various stages of their development

The following stages in lymphoid patches (LP) development have been revealed: I-1-6, II-7-14, III-15-21, IV-22-30 days; during these periods lymphoid noduli with germinative centers, cupolae and internodular areas are formed. Amount of all kinds of cells in the LP parenchyma and their rearrangement in the zones takes place. In one-month-old rats blast forms predominate in the LP germinative centers, and small lymphocytes--in the zone of small lymphocytes of the noduli and internodular areas. Under conditions of antenatal effect of an antibiotic on the system mother--fetus there is no disturbances in formation of the anatomical structures. However at each stage of development the small intestine LP are not mature, concerning their cellular composition. Amount of cells decreases, their interrelationship changes. Lympho- and plasmocytopoiesis decreases.     

Microscopic anatomy of small-intestinal lymphoid patches in children and adults

Longitudinal histological sections of lymphoid patches (LP) in the small intestine, stained after van Gieson and with hematoxylin--eosin, obtained from 105 corpses of persons at the age of 0 up to 90 years have been studied. The LP parenchyma is presented as accumulation of lymphoid nodules++ with a germinative center, or without it and diffuse lymphoid tissue. The lymphoid nodules++ situate both in the mucous membrane and in the submucous tela of the small intestine. The area of the LP components in the newborns is the greatest--84% from the whole area of the LP section. During the human life it decreases and by the old age it makes 47%. The lymphoid nodules++ area with the germinative center in the newborns makes 21% from the area of the LP section, in children from 1 to 3 years of age it increases up to 50%, then it gradually decreases and in the elderly age it makes only 3.8%. The diffuse lymphoid tissue in the LP composition is revealed in all age periods. Size of the lymphoid nodules++ patches, situating in the jejunum and ileum walls in the newborns is the same. In children at the age of 10 days--12 years the LP nodules++ in the ileum are larger than those in the sejunum. The size of the LP noduli increase up to the period of the second childhood then decreases. The height of the lymphoid noduli in persons of mature, elderly and old ages decreases twice in comparison with the children of 3-12 years of age.     

Afferent neural pathways in cough and reflex bronchoconstriction

Cough and bronchoconstriction are airway reflexes that protect the lung from inspired noxious agents. These two reflexes can be evoked both from the larynx and tracheobronchial tree and also from some extrarespiratory sites. Within the airways, certain sites are particularly sensitive to stimulation of cough (larynx and points of proximal airway branching), whereas bronchoconstriction can be triggered from the whole of the tracheobronchial tree. In the larynx, "irritant" receptors with myelinated afferents mediate cough and bronchoconstriction. Little seems to be known about laryngeal nonmyelinated afferents and their reflexes. In the tracheobronchial tree and lung, slowly adapting stretch receptors (SARs) and rapidly adapting stretch receptors (RARs) have opposing effects on airway tone, the former mediating bronchodilation and the latter bronchoconstriction. In cough, on the other hand, they operate concurrently, a mediatory role for RARs and a facilitatory role for SARs. C-fiber endings (bronchial and pulmonary) mediate bronchoconstriction. Inhalation of so-called "selective" C-fiber stimulants induces cough, but excitation of RARs has not been eliminated, and the possibility also exists that the cough is secondary to other lung actions mediated by these nerve endings. Although cough and bronchoconstriction may be mediated by the same type of receptor, they seem to have separate afferent neural pathways.     

Changes in the iliac lymph node of the rat in aseptic uterine inflammation and during its correction]

In the lymphoid tissue of the iliac lymph node at an aseptic inflammation in the uterus the greatest changes have been revealed in 48 h from the moment, when the foreign body has been introduced. They are manifested at the tissue level (increasing content of macrophages, lymphoblasts, large lymphocytes, plasmoblasts, immature plasmocytes, mast cells, neutrophils), as well as at the organic level (increasing amount of secondary lymph noduli, increasing area of the paracortical zone, decreasing area of the cortical plateau, of the medullary intermediate sinus, medullary cords). Use of carbomineral sorbents ensures correction of the inflammation; this is demonstrated as reduction of reactive changes in the regional lymph node.     

Mesenteric lymph nodes in the rat after exposure to hydrocortisone

The construction and cell composition of the cortex and medulla have been morphometrically studied after 1-, 3-, 5-, 7- and 14-aliquot injection of medical doses of hydrocortisone (0.25 mg per 100 g of body mass). The body mass of the animals decreases, as does the size of the mesenteric lymph nodes. The lymphocyto- and immunocytopoietic functions intensify in the medullary cords with a simultaneous inhibition of these processes in the cortical plateau and in the lymphoid noduli. On the 5th and 7th days there is some increase in the section area of the cortex, while that of the medulla decreases. The part of small lymphocytes in these structures grows large. Therefore, it is possible to suppose a definite tendency towards restoration of the structural components within two weeks.     

Morphofunctional changes in the lymph nodes and microcirculatory bed of small-intestinal mesentery of dogs in septic peritonitis after endolymphatic administration of ampicillin

With the aim to study effectiveness+ of endolymphatic (EL) administration of ampicillin (AC), using the model of an acute diffuse septic peritonitis in dogs, the morphological and morphometrical investigation has been performed concerning the state of the lymph nodes (LN), which are regional as regards the pathological focus (pelvic) and remote (tracheobronchial, mesenteric) and hemomicrocirculatory bed (HMCB) of the small intestine mesentery. All LN groups studied are involved in the pathological process, that produces certain increasing disturbances in the structure and cell composition in LN. In 6 h the changes are especially manifested in the pelvic LN, and in 18 h--in the animals without application of AC, or at its intramuscular injection LN lose their typical structure. Their dimensions and number of lymphoid nodules++ and medullary cords decrease, a sharp impoverishment of lymphocytes in LN is observed. By this time critical disturbances in the HMCB structure develop; they are characterized as presence of great amount of avascular areas in the mesentery, extended capillary loops, plasmatic saturation of interstitium. When AC is injected endolymphatically, simultaneously with peritonitis modelling T- and B-dependent zones in LN are preserved, a high volumetric part of lymphocytes is kept in all groups of LN, structure and function of HMCB are normalized. The pronounced delay in development and decreasing manifestation of infective-toxic disorder in LN and HMCB depend on effective concentrations of the antibiotic, produces in the lymphatic system.     

Intra-airway thermodynamics during exercise and hyperventilation in asthmatics

To determine whether exercise and hyperventilation produce the same intrathoracic thermal events in asthmatics, we used a thermal probe to record airstream temperatures during both stimuli at multiple points within the tracheobronchial tree. From these data, the global and regionally distributed exchanges of water and heat that occurred throughout the respiratory tract were calculated. During each provocation, intra-airway temperatures fell equivalently, thereby producing similar intrathoracic water fluxes and heat transfers. Neither stimulus was associated with airway drying, and both resulted in similar distributed losses of thermal energy from the tracheobronchial tree despite small regional heat and water exchanges. The degree of airway obstruction was identical after both challenges; however, the onset of airway narrowing was earlier with hyperventilation and developed in association with more rapid rewarming. These data demonstrate that the hyperpnea of exercise and hyperventilation produce identical thermal consequences within the respiratory tract of asthmatics.     

A unique cell type in the lung--the Clara cell (the non-ciliated bronchiolar epithelial cell)

The non-ciliated bronchiolar epithelial cells (the Clara cells) are found most frequently in the distal conducting airways, but they are found throughout the tracheobronchial tree of different mammalian species. According to recent data, the main functions of the Clara cells can summarized as (1), the secretion of certain components of the extracellular bronchiolar lining layer (2), metabolism and detoxification of xenobiotics and other toxic compound (3) and participation in the renewal process of the bronchiolar epithelium. The main goal of this paper is to collect and discuss some of the general features of Clara cells from a functional-morphological point of view, and their possible role in pathological alterations of the lung especially in the pathogenesis of lung tumours originated from Clara cells.     

A study on tracheobronchial deposition and 2-hour retention in rabbits.

Deposition of well-defined test aerosols of polystyrene particles was studied in rabbits. The deposition was estimated in a standardized part of the tracheobronchial tree following free dissection of the bronchial parts. Ten rabbits were exposed to a mixture of two test aerosols of about the same size(6-7 mum) tagged with 51-Cr and 46-Sc, respectively. There were interindividual differences in tracheobronchial deposition but a correlation (r equals 0.98) between 51-Cr and 46-Sc tagged particles. Eleven rabbits were first exposed to the 46-Sc tagged aerosol and 2 hours later to the 51-Cr tagged aerosol. In this experiment there was also a correlation (r equals 0.74) between the tracheobronchial deposition of 51-Cr tagged particles and the 2-hour retention of 46-Sc tagged particles. This result together with results from an earlier study indicate that the large interindividual differences in deposition are real and are not caused by differences in exposure technique, or in the aerosols.     

Morphological aspects of human lymphoid cells grown in vitro

Summary An established immunoglobulin-producing human cell line exhibits a variety of morphological entities described as reticular, lymphoid, and plasmacytoid cells. Transitional forms are frequent, and time lapse photomicrography experiments demonstrate morphological interconversion. The round forms and their morphological precursors synthesize immunoglubulin and constitute about 44% of the cell population. This cell line displays a variety of morphological and functional properties assigned to in vivo lymphoid cell series. It is proposed as an in vitro model for the study of lymphoid cells. Supported by Grant CA06939-05 and by Special Research Career Development Fellowship Award 1F03 CA42078 from the United States Public Health Service.     

Morphological aspects of human lymphoid cells grown in vitro

Summary An established immunoglobulin-producing human cell line exhibits a variety of morphological entities described as reticular, lymphoid, and plasmacytoid cells. Transitional forms are frequent, and time lapse photomicrography experiments demonstrate morphological interconversion. The round forms and their morphological precursors synthesize immunoglobulin and constitute about 44% of the cell population. This cell line displays a variety of morphological and functional properties assigned to in vivo lymphoid cell series. It is proposed as an in vitro model for the study of lymphoid cells Supported by Grant CA06939-05 and by Special Research Career Development Fellowship Award 1F03 CA42078 from the United States Public Health Service.     

Morphocytochemical reaction of the lymph nodes in dogs to the administration of lysozyme

By means of morphological, morphometrical and histochemical methods pelvic and tracheobronchial lymph nodes have been studied in dogs and concentration of lysozyme has been estimated in blood serum, in lymph and the lymph nodes after a single intramuscular injection of lysozyme (2 mg/kg of body mass). In the material investigated total concentration of lysozyme reaches its maximal values in 6 h after injection, then it gradually decreases and in 48 h reaches its control level. Morphometrically changes in cell composition are revealed predominantly of immune-competent cells in T- and B-dependent zones of the lymph nodes. Thus, the volumetric part of lymphoblasts in the germinative centers of the lymphoid nodules reaches its maximal indices by 48 h after lysozyme injection, while plasmatization of the paracortical zone and of medullary cords increases up to the 7th day. By the 14th day the volumetric part of lymphoblasts, immunoblasts and plasmocytes decreases gradually, and in 21 days after injection of the drug contents of the blast forms of the cells in the structural-functional zones of the lymph nodes does not differ from that in the control. The data obtained demonstrate the immunomorphological rearrangement of the lymph nodes in response to the exogenic lysozyme administration.     

Growth of the ferret tracheobronchial tree

Because the ferret is being used increasingly in inhalation toxicology and lung physiology studies, it is necessary to better understand the airway structure of its tracheobronchial tree. Previously published information does not include dimensions of bronchi and bronchioles in either adult or growing ferrets. The airway structure of interest for calculating inhaled particle deposition patterns includes airway lengths, diameters and branching angles in each generation. Measurements of these dimensions were obtained for several selected airway paths on replica casts. Casts were made in-situ in four male litter mates age 14 hours, 9.5 days, 16.5 days and 56 days. These data demonstrate, that as with human lung growth, body length at a given age is a good predictor of airway lengths and diameters. Airway branch angles do not appear to change significantly during growth. Sufficient measurements were made to provide dimensions of a typical tracheobronchial pathway for this species. This pathway begins with the trachea and ends at the terminal bronchiole. The morphometric data were not sufficient to determine whether or not the number of tracheobronchial generations increase or decrease postnatally.     

Bone marrow cells as affected by staphylococcal toxin against a background of overheating of the whole body

The electron microscopic study of the material demonstrates that after injection of staphylococcal toxin in combination with high temperature, in the bone marrow cells of the animals certain ultrastructural changes are observed already from the first day of the experiment and they progressively increase. Especially essential changes are observed in the cells of erythroid and granulocytic sprouts. In elements of lymphoid and megakaryocytic sprouts morphological changes are manifested to a less degree. Sometimes in vacuoles irregular formations of high electron density are localized.     

Identification of monocytic nature in acute undifferentiated leukemia by in vitro marrow culture study

We report a case with acute undifferentiated leukemia whose leukemic blasts lacked morphological, cytochemical and immunological features of lymphoid or myeloid differentiation. The in vitro culture study defined her leukemia as of monocytic origin. Her marrow blasts underwent monocytic differentiation with strong nonspecific esterase activity when cultured in a liquid system with human placental conditioned medium. The semisolid agar culture showed an AML-type growth pattern. The present study indicates that in vitro culture study can be used as a supplement to improve the classification of certain unclassifiable leukemias.     

Determining deposition sites of inhaled lung particles and their effect on clearance

An essential component of lung defense is clearance of particulates and infectious vectors from the mucus membrane of the tracheobronchial tree and the alveolar regions of the lung. To partition clearance between these areas we determined the bronchial branching pattern, the anatomical sites of particle deposition, and subsequent clearance in the same animal. Using a 2.85-microns particle tagged with 57Co for inhalation and deposition in the sheep lung, we followed clearance via a series of computer-stored gamma-scintillation lung images. The same sheep was reinhaled, and the particle distributions for both inhalations were compared. After the animals were killed, the bronchial branching pattern and length of the bronchial tree were documented. The number of particles depositing in all bronchi down to 1 mm diam was determined by scintillation counting, and the number in respiratory bronchioles and alveoli was microscopically counted. We conclude that particles deposited in bronchi greater than or equal to 1 mm diam clear in 2-4 h postdeposition. Bronchi distal to 1-mm-diam bronchi and alveoli clear evenly over 72 h, and the number of particles equal to the tracheobronchial deposition cleared after 45 h.