Age and features of the content of myelinated fibers in nerves of the splenic plexus of man

The amount of the myelin fibers (MF) has been calculated in transversal serial sections of the nervous-vascular complexes of the splenic artery in newborns, in persons of mature (the 1st and 2d periods), elderly and old ages. In each age group 20 complexes have been studied. The total amount of the MF in persons of mature age (the 1st period) in 4.2-6 times greater (initial--terminal parts of the plexus) than in newborns, in the persons of old age it is 4-2.1 times less than in persons of mature age (in both cases P less than 0.001). Thin MF predominate, their relative contents in the aggregate of all classes of the MF in newborns are 92%, in mature persons--87%, in old persons--65%. Decreasing part of the thin MF together with increase of their absolute amount in the mature persons, comparing to the newborns, depends on higher rates in differentiation of middle and thick MF. Phenotyping peculiarities and stages of productive development, stabilization (the 1st-2d periods of the mature age), involutions of the nerve connections are defined in the splenic artery. The amount of the MF predominates in the nerves of the initial part of the plexus comparing to its terminal part. There is a direct correlative dependence between the amount of the MF in the plexus nerves and the size of the lumen in the splenic artery. Changes in the amount of the MF of different classes reflects qualitative differences of the splenic innervation relations at certain stages of the human postnatal development.     

Comparative evaluation of age-related and organic characteristics of the structure of the adventitial nerve plexuses in human arteries

It has been stated by means of morphometric investigation of transversal sections of the nervous-vascular complexes of the thyroid, splenic and brachial arteries, stained after Weighert-Pahl, that in the human being during the first mature period the amount of nerves in adventitia of nervous arteries is 1.4-2.7 times greater than in the newborn, and in the old man--1.3-1.6 times less than in the mature person. Average total area of the nervous transversal sections changes in the same proportion with age. The age factor is the leading cause in increasing amount of nerves and the total area of their sections at the stage of productive development of the plexuses, as well as in decreasing of these indices in ageing process. In each age group the amount of nerves is proportional to the diameter of the artery lumen and to the organ's mass (spleen). The greatest amount of nerves at all stages of human development occurs in the adventitial plexuses of the thyroid arteries; they are less numerous in the plexus of the splenic artery, and their minimal amount is noted in the plexus of the brachial artery. Most of the nerves in adventitia of the arteries have microscopical diameter (less than 70 mcm), serve for selective, discrete innervation of the arterial wall.     

The microscopic anatomy of the human pharyngeal tonsil in the postnatal period of ontogeny

Histological sections of the pharyngeal tonsil (PhT) have been investigated in 55 corpses of persons of both sex and various age, that had no disease connected with lesions of the PhT by the time of their death. The aim of the work is to determine relative areas of each structural element of the PhT in comparison to the whole section area taken as 100%. The PhT lymphoid tissue reached its maximal relative development at the first childhood. Then the lymphoid tissue area in the PhT histological sections decreases gradually, making already in the second mature age one half of the tonsil section area, and in the elderly age--nearly one-fourth. The decrease of the relative lymphoid tissue area takes place at the expense of decreasing area of the lymphoid nodules. The relative area of the connective stroma increases inversely to the relative decrease of the lymphoid tissue area parameters. The germinative centers in the lymphoid nodules are absent in newborns and old persons. The greatest value of the relative area of the germinative centers falls to the early infancy. The lymphoid nodules with the germinative centers, according to their relative area during all age periods, besides the newborn period, the second mature, elderly and old age periods, essentially exceed the area, that occupy the nodules without the germinative centers on the PhT sections.     

Anatomy and topography of the tracheobronchial lymph nodes in man during the postnatal period of ontogeny

Tracheobronchial lymph nodes (TBLN) have been studied in 71 corpses of persons at different ages. The TBLN are revealed by means of polychromic injection of Gerota mass into the lung tissue, or directly into the lymph nodes revealed. The number of the inferior and superior (right and left) TBLN varies within a wide range. Longitudinal dimentions of the lymph nodes increase with age. A certain age dependence in topography of the inferior and superior TBLN is stated. In persons of mature and elderly age, dextrobronchial type in arrangement of the inferior TBLN is found more often, and at younger age periods--even type of their arrangement is specific. The right superior TBLN in newborns, children and adolescents possess an evenly concentrated type of localization, and at later age periods--dispersive and unevenly concentrated. The superior left TBLN in newborns and children are mainly situated in the TB angle area, in persons of mature and elderly age--on the lateral surface of the thoracic part of the trachea. The form of the TBLN depends on their localization. A certain relation is determined between the localization of the inferior TBLN and the number of the superior (right and left) TBLN.     

Quantitative microscopic characteristics of cardial glands in in the human esophagus in postnatal ontogenesis

Microscopical investigation of oesophagus, obtained from corpses of 33 men and 33 women has been carried out (staining with hematoxylin and eosin, van Gieson). The cardial glands have been revealed in 92.4% of cases in the inferior and in 4.6% of cases in the superior third of the oesophageal wall. They have not been revealed in the superior third of the oesophageal wall. They have not been revealed in its medial third. Amount of acini in the section is essentially changeable. In elderly and old persons the ducts of the glands often form ampullar dilatations. The acinar areas on the section remain stable during the greatest++ period of the postnatal ontogenesis and only during old age they decrease slightly. The proper plate of the mucous membrane in the inferior part of the oesophagus in the zone, where the cardial glands are situated, is always thicker than in the area free from the acini. Close interrelations have been revealed between the cardial glands and lymphoid tissue of the oesophageal wall. The intensity of the glandular-lymphoid interrelations is insignificant in newborns and in children of suckling age. It is maximal in persons of mature and elderly age. Remaining at a sufficiently high level, the glandular-lymphoid associations in old persons are manifested in a less degree than in the previous age groups. No difference in organization of the cardial glands has been revealed in the superior and inferior parts of the oesophageal wall, as well as any sex peculiarities.     

Age-related characteristics of the myeloarchitectonics of the peripheral nerves

By means of macromicroscopy and microscopy myeloarchitectonics of morphologically and functionally different somatic and visceral nerves (branches: mandibular nerve, cervical spinal nerves, inferior laryngeal nerve, hepatic plexus) have been studied in 11 age groups. During the prenatal period of ontogenesis asynchronism of myelogenesis is stated in various muscle branches of the nerves, dependent on formation of function in corresponding muscles and muscle groups. As demonstrate investigations on peculiarities of myelogenesis course in the somatic and visceral nerves studied, during the period of pre- and postnatal ontogenesis, its dynamics embraces three stages of myelogenesis, determined by G. B. Stovichek for visceral nerves: productive myelogenesis, stages of stabilization and involution. The stage of productive myelogenesis in the somatic nerves studied lasts up to the end of the adolescent period. Two phases are determined in it: the first lasts up to 2-3 years; the second--up to the end of the adolescent period and is characterized with a complete formation of the myelin fibers spectrum. In the visceral nerves studied increase of general amount of myelin fibers and their differentiation are completed simultaneously during the adolescent age. The stabilization stage of myeloarchitectonics of the nerves studied corresponds to the mature age (I and II periods) and the involution stage--to the elderly (and old) age.     

Age-related aspects of the anatomy and topography of the human tubal tonsil

The tubal tonsil (TT) has been investigated in 60 preparations of the auditory tube (right and left), obtained from 30 corpses of persons at various age, those died from traumas and having neither any pathological changes in their acoustic organs, nor chronic inflammatory diseases by the time of death. The TT is presented as a solid or interrupted lymphoid tissue plate, situating in the mucosal membrane in the area of the pharyngeal opening to some extent in the inferior, posterior and anterior walls of the auditory tube. In newborns the TT is presented as a diffuse lymphoid tissue, where lymphoid nodules begin to form. The greatest amount of the lymphoid nodules in the TT are revealed in the infantile age and this sign is kept during subsequent age periods, including the first period of mature age. During these age periods on the surface of the mucosal membrane in the area of the pharyngeal opening numerous small eminences are seen--tubercles, corresponding in their position to lymphoid nodules under them. Beginning from the second mature period and up to old age the amount and size of the lymphoid nodules in the TT decreases. At that time on the surface of the mucosal membranes in the area of TT only single tubercles are revealed.     

Determination in the system of the neuromuscular relations of the coronary arteries at stages in human postnatal development

By means of micromorphometric method in transversal sections of electively stained right and left coronary arteries the data, characterizing the area of the middle and external sheaths, amount of myelin fibers in nerves, accompanying the artery have been obtained in men of 8 age groups (from birth up to old age), who died from causes not connected with the cardiovascular pathology. The summary amount of all classes of myelin fibers increases synchronously with an increase of the muscle sheath area from newborn up to 35-45 years of age. After this age the amount of the myelin fibers decreases together with decreasing area of the middle sheath. Minimal values of these indices are observed in the old age (85-90 years). The external sheath area increases permanently from birth up to the old age. The correlative analysis reveals a positive and significant connection of various degree between the myelin fibers number and value of the middle arterial sheath in persons of juvenile, mature and elderly age: amount of the muscular layer is adequate to the myelin fibers amount. In other age groups the correlative connections are either small, or not significant. Alternative, corresponding to each age quantitative gradations of the nervous connections are determined by means of the peripheral substrate. Its role in the vessels investigated is performed, to a definite degree, by the muscle sheath.     

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.     

Individual and age variability of the anatomy and topography of the human lymph nodes

Analysis of the author's and literature data revealed two peculiarities in the lymph node anatomy. One of them is characterized with a great variability of amount and size of the nodes in every regional group. The second peculiarity is that age involution of the lymphoid tissue in the nodes is demonstrated in elderly and old persons as a decreasing amount of the lymph nodes and as their enlargement.     

Qualitative composition of the normal intestinal microflora in individuals from the various age groups

The study of the microflora of the large intestine in healthy adult volunteers of different age groups (25-36, 55-68 and 88-94 years old), living in Switzerland, has been carried out. As revealed by the analysis of the result obtained in this study, normal intestinal microflora in adults has different qualitative and quantitative characteristics at different periods of their life. The greatest diversity of intestinal microflora is observed at a mature age (55-68 years old), while the poorest microflora is observed in people more advanced in age. The amount of microorganisms inhabiting the intestine reaches its maximum in people of mature age and is low in elderly people. Changes in normal intestinal microflora are probaly linked with morpho-functional transformations in the host body at different periods of life. It is expedient to work out the criteria of norm for the microflora of different age groups with a view to use these criteria for the evaluation of the microbial status of the intestine in persons of different age.     

Time trends of thyroid cancer incidence in Belarus after the Chernobyl accident.

The rates of childhood thyroid cancer incidence observed in Belarus during the period 1986 to 1995 are described as a function of time after exposure, age at exposure, and sex. Conclusions are drawn for the excess absolute risk function. After a minimum latent period of about 3 years after exposure, this risk function has a linear increase with time for at least 6 years. After correction for the dependence of average doses on age, the radiation-induced absolute thyroid risk in Gomel is about a factor of 3 higher for children up to age 10 at exposure compared to older ones; this may be due in part to different case-collection quality. In addition, in the group up to 10 years at exposure, the thyroid of girls is more sensitive to radiation by a factor of about 1.5 than the thyroid of boys on an absolute scale. Risk estimates from external exposure are consistent with risk estimates from Gomel assuming that the increase in excess cases reaches a plateau soon.     

Lymphoid structures in the wall of the human esophagus during postnatal ontogenesis

Lymphoid aggregates in the wall of the human oesophagus have been studied in corpses of 107 persons died a sudden death and who had not any disease in the digestive organs and in the immune system (total plane preparations, slices stained with hematoxylin--eosin, azure-2-eosin and after van Gieson). The lymphoid aggregates are arranged as longitudinal chains. Their number increases from birth towards the second childhood, and then decreases towards the old age. In the upper oesophageal parts these aggregates are more numerous than in the lower ones. The lymphoid aggregates look like convexoconvex lenses. Their size is maximal during the second childhood, the longitudinal dimensions are nearly two times as great as their thickness. With time, the sizes of the formations become small. The arrangement density of the lymphoid cells in the subepithelial layer of the mucous membrane is maximal in newborns, and then it decreases up to the old age. The lymphoid aggregates are situated in the oesophageal wall, mainly, near the ducts of the oesophageal glands.     

Individual quantitative differences in the structure of the human hippocampus

The volume of the hippocampal grey substance (Corpus Ammoni--CA) and that of the denticulated plate (Fasciculus dentatus--FD) have been studied in mature persons of various sex and age (17 subjects, 22 cerebral hemispheres) under cytoarchitectonic control defining the borders of the cerebral formations mentioned. Certain quantitative and spatial differences of CA and FD have been revealed in some subjects. Especially great differences are noted between more seldom occurring extreme individual variants, their difference being as great as three times. The differences revealed are demonstrated to be independent on the brain mass of the human beings studied. The observation performed causes to revise the competency of the principle concerning a constant proportional dependence between the reference points on the cerebral surface and the internal cerebral structures. These data are used in neurosurgery when surgical interventions are performed on brains with different dimensions. A suggestion is made that the individual volumetric differences revealed in the hippocamp of various persons are defined by its functional specificity.     

Lymphoid nodules of the urinary bladder in man

Basing on macro- microscopical investigation of the urinary bladder in 94 persons, died at the period of birth up to old years and by the time of death having not any disease of the urinary apparatus, structure and topography of the lymphoid nodules, their amount, density of distribution in the mucous membrane of various parts of the organ have been studied. The germinative centers in the lymphoid nodules of the urinary bladder are not revealed. The external appearance of the nodules is not the same; some have clear contours others have no clearly manifested borders. We call them prenodules. The lymphoid nodules are situated near to each other without any definite order. And only near the ureteral openings they are always revealed in a small amount, in the area of the triangle; they are oriented, as a rule, from the ureteral openings towards the exit from the urinary bladder. The amount of the lymphoid nodules in the organ's wall varies (at an average) from 18, in newborns, up to 415, in adolescents, and up to 129, in old persons. Distribution density of the lymphoid nodules in the fundal area of the urinary bladder is somewhat greater, than in its superior parts. The size of the lymphoid nodules during all age periods is not more than 900 mcm.     

Thyroid cancer risk in Belarus after the Chernobyl accident: Comparison with external exposures

Within the time period 1990–1993, childhood thyroid cancer incidence due to the Chernobyl accident increased dramatically in Belarus, especially with regard to the birth cohort January 1, 1971, to May 31, 1986. This rise subsequently slowed down, i.e. during the period 1994–1996. The respective data were analysed and compared with the results of an analysis on the time dependence of thyroid cancer incidence in a pooled cohort of persons who had been exposed during childhood to external radiation with high dose rates. Concerning the period of 5–10 years following exposure, the excess absolute cancer risk per unit thyroid dose in the latter (external) exposure group was found to exceed the one in the Belarus group by a factor of two. This difference, however, is not statistically significant. The age-adjusted average excess absolute risk per unit thyroid dose for the period of 5–50 years following external childhood exposure was found to be 8 female and 14 male cases per 10⁴ person-year · Gy, which is a factor about 2.5 times higher than for the non-adjusted risk in the pooled cohort, as reported by Ron et al. in 1995. Assessments of future excess thyroid cancer cases due to the Chernobyl accident were done on the basis of the time dependence of thyroid cancer risk following external exposure. The thyroid cancer incidence among the birth cohort considered in Belarus and for a period starting from the cessation of the available observation data (1 January 1997) and extending to 50 years after the Chernobyl accident has been estimated to be about 15,000 cases, with an uncertainty range of 5000–45,000 cases. According to our calculations, 80% of these cases exceed the baseline risk under enhanced thyroid surveillance. Received: 8 June 1999 / Accepted in revised form: 20 November 1999     

Dental Status in the Elderly: A Review of the Swedish Literature1

1. Elderly persons living in their own homes have over the past 20 years tended to retain an increased number of natural teeth. This tendency is confirmed especially in the ongoing studies by Tor Österberg, nr 12 and 13. These studies indicate a decreasing edentulous part of the 70-year old cohorts from 1971, 1976 and 1981. 2. Elderly persons dependent on institutional care are edentulous in as high degree today as 20 years ago. According to this criterion, therefore, their dental health has not improved. 3. Dentures worn by elderly persons frequently are defective in fit and function. For the general wellbeing and health in later life, mastication of a well-balanced diet and lack of discomfort from denture-bearing mucosal surfaces are important. Information in this respect and measures to improve masticating function are greatly needed among persons in the higher age groups, whether living at home or in institutional care. 4. Caries activity is increasing among elderly persons. 5. Periodontitis (loosening of the teeth) is very frequently found in elderly persons. 6. Oral hygiene requires improvement. 7. Among the elderly, living in their own homes or in institutions, the need for odontologic care is objectively great, but the demands currently made are remarkably low. 8. Of the aged in institutional care, about 75 per cent are suitable for measures of oral care. A change in dental health seems to be slowly taking place among the elderly, in that increasing numbers keep more of their own teeth longer in life. The demands made by the high age groups on the odontologic services, though increasing, are still very low relative to the objective and consequently great accumulated needs. This contrast is especially pronounced among geriatric patients in institutions. An aggressive, searching approach to both restorative and preventive oral care in the higher age groups is of pressing importance if optimum conditions for eating and chewing late in life are to be achieved. For timely counteraction of the tendency to a more passive attitude t o dental care that commonly accompanies rising age, information on these matters should be energetically disseminated among persons due for retirement or new-l y retired.     

Dependence of the topography of the hepatic veins on the external shape of the liver, its size and on age

Hepatic preparations obtained from 186 newborns, children and mature persons have been studied. In newborns and babies the size of the right and left hepatic lobes are nearly the same. Beginning from an early age, the right hepatic lobe begins to grow, and the oblongatal or oval form of the liver changes into a triangle one. With changes in its size and form, the topography of the hepatic veins changes, too. In children younger than 1 year of age having the oblongatal or oval form of their liver, the diameters of the right, middle and left hepatic veins are nearly equal. In mature persons having the triangle form of the liver, the right hepatic vein is the largest and its diameter is twice as large as that of the left hepatic vein. Additional hepatic veins flowing into the inferior vena cava, are mainly formed by the branches participating in drainage of the right hepatic lobe. In 25 cases there are additional large hepatic veins; they are observed in cases when the right hepatic vein is poorly developed.     

Drivers of seedling survival in a temperate forest and their relative importance at three stages of succession

Negative density dependence (NDD) and niche partitioning have been perceived as important mechanisms for the maintenance of species diversity. However, little is known about their relative contributions to seedling survival. We examined the effects of biotic and abiotic neighborhoods and the variations of biotic neighborhoods among species using survival data for 7503 seedlings belonging to 22 woody species over a period of 2 years in three different forest types, a half‐mature forest (HF), a mature forest (MF), and an old‐growth forest (OGF), each of these representing a specific successional stage in a temperate forest ecosystem in northeastern China. We found a convincing evidence for the existence of NDD in temperate forest ecosystems. The biotic and abiotic variables affecting seedlings survival change with successional stage, seedling size, and age. The strength of NDD for the smaller (<20 cm in height) and younger seedlings (1–2 years) as well as all seedlings combined varies significantly among species. We found no evidence that a community compensatory trend (CCT) existed in our study area. The results of this study demonstrate that the relative importance of NDD and habitat niche partitioning in driving seedling survival varies with seedling size and age and that the biotic and abiotic factors affecting seedlings survival change with successional stage.     

Capillaries of the intrinsic nerves of human skeletal muscles

Development of blood capillaries in the human intraorganic nerves has been studied. The intramuscular nerves of fetuses, newborns, children and mature persons (88 cases in all) make the object of the investigation. Combination of light optic methods and electron microscopy is used. The development of blood capillaries of the human intraorganic nerves is a complex process, indissolubly connected with development of myelin and amyelin conductors. The capillaries in the nerves appear on the 3d month of the intrauterine development and their structure is the most favourable for intensively proceeding, at this time, the myelinization process. With progress of nervous fibers and stromal elements, differentiation of the blood capillaries takes place. By the 6th month of the interuterine life, the capillaries of the intramuscular nerves are mainly formed. The structural unit in interrelation of the capillaries and nerve elements is the complex: capillary-lemmocyte-nervous fiber. Further changes are of slower character.