Cement gland as the adhesion organ in Xenopus laevis embryos

The cement gland in batrachians is a temporal ectodermic organ which is necessary for an embryo's attachment to the substrate. In this review, some notions about the origin of the cement gland of Xenopus laevis frogs, its functioning, genes being expressed in it, and regulation of its formation and development are provided. The role of some homologies of agrgenes of the cement gland in Xenopus laevis is noted at different conditions of other animals and man.     

Quantitative study of the capillaries in a secreting salivary gland (electron-microscopic and morphometric analysis)]

Regularities in structural rearrangement of epithelium of blood capillaries in the rat parotid salivary gland have been studied under various functional conditions of the organ. The data obtained demonstrate that secretion is accompanied by dilatation of anuclear segments of capillary endothelium, decreasing thickness of endotheliocytes, rise of hematocrit number by adding the total area of the capillary fenestrated surface, the form factor of intraendothelial contacts and decreasing length of the contacting cytolemmas. Since extreme values of the metrical parameters studied have been revealed during the phase of the secrete excretion, a suggestion is made that increasing hydraulic permeability of the metabolic vessels with subsequent transport of the fluid to the terminal parts of the gland create the conditions promoting to reach the threshold level of pressure in acini that is necessary to overcome high resistance of nerrow intercalated sections for the secretion to reach the ducts.     

Cement gland as the adhesion organ in <Emphasis Type="Italic">Xenopus laevis</Emphasis> embryos

The cement gland in batrachians is a temporal ectodermic organ which is necessary for an embryo’s attachment to the substrate. In this review, some notions about the origin of the cement gland of Xenopus laevis frogs, its functioning, genes being expressed in it, and regulation of its formation and development are provided. The role of some homologies of agr genes of the cement gland in Xenopus laevis is noted at different conditions of other animals and man.     

The antecubital organ of the primate slow loris (Nycticebus coucang coucang)

A study of the ‘antecubital organ’ of the slow loris (Nycticebus coucang coucang), was undertaken in light and electron microscopes. As distinct from other prosimian primates there is a complete absence of interstitial cells in the gland suggesting its different functional role. The acinar cells in the ‘antecubital organ’ of slow loris contain large number of smooth ER and electron-dense secretory granules. The granules are seen both in the apical region of the cells as well as in their basal cytoplasmic processes. Some of these processes appear to terminate close to a blood capillary. The structural features of the ‘antecubital organ’ of slow loris suggest that it is a mixed gland of both exocrine and endocrine nature.     

Microcirculatory bed in the capsules of certain glands]

The capsules of the thyroid, submaxillary salivary, pancreatic gland of adults and the thymus of children were studed. The preparation were impregnated with silver nitrate after Kuprijanov and stained with haematoxiline-eosin. Different constructions of them microcirculatory bed depending on the character of the tissue and the functional activity of the organ were found. The value of the total cross section of the vessels of the microcirculatroy bed calculated in the capillary link allowed a comparisonof the degree of blood supply of the sheaths. The vascular bed of the sheaths served as anadditional way for the blood supply of the organ, a distribution basin and the site ofcollection of the blood, flowing from the parenchyma through collateral vessels.     

Physiology of the epiphysis: Modern concepts

In this review, the information available from the literature and the data obtained by the author about the epiphysis (or the pineal gland), an important neuroendocrine organ, and about its main hormone, melatonin, are summarized. The history of studying the epiphysis and the evolutionary aspects of its activity, anatomy, and physiology are discussed. The results of electrophysiological studies are described, and biochemical aspects of the epiphysis activity are analyzed. The pathways through which photoinformation enters the pineal gland, and external factors regulating its functioning are described in detail. The data on the physiological effects produced by epiphyseal neurohormones (melatonin is the best studied) and their role in formation of different types of behavior are emphasized.     

The Role of the Microenvironment in Mammary Gland Development and Cancer

The mammary gland is composed of a diverse array of cell types that form intricate interaction networks essential for its normal development and physiologic function. Abnormalities in these interactions play an important role throughout different stages of tumorigenesis. Branching ducts and alveoli are lined by an inner layer of secretory luminal epithelial cells that produce milk during lactation and are surrounded by contractile myoepithelial cells and basement membrane. The surrounding stroma comprised of extracellular matrix and various cell types including fibroblasts, endothelial cells, and infiltrating leukocytes not only provides a scaffold for the organ, but also regulates mammary epithelial cell function via paracrine, physical, and hormonal interactions. With rare exceptions breast tumors initiate in the epithelial compartment and in their initial phases are confined to the ducts but this barrier brakes down with invasive progression because of a combination of signals emitted by tumor epithelial and various stromal cells. In this article, we overview the importance of cellular interactions and microenvironmental signals in mammary gland development and cancer.The mammary gland is composed of a combination of multiple cell types that together form complex interaction networks required for the proper development and functioning of the organ. The branching milk ducts are formed by an outer myoepithelial cell layer producing the basement membrane (BM) and an inner luminal epithelial cell layer producing milk during lactation. The ducts are surrounded by the microenvironment composed of extracellular matrix (ECM) and various stromal cell types (e.g., endothelial cells, fibroblasts, myofibroblasts, and leukocytes). Large amount of data suggest that cell-cell and cell-microenvironment interactions modify the proliferation, survival, polarity, differentiation, and invasive capacity of mammary epithelial cells. However, the molecular mechanisms underlying these effects are poorly understood. The purification and comprehensive characterization of each cell type comprising normal and neoplastic human breast tissue combined with hypothesis testing in cell culture and animal models are likely to improve our understanding of the role these cells play in the normal functioning of the mammary gland and in breast tumorigenesis. In this article, we overview cellular and microenvironmental interactions that play important roles in the normal functioning of the mammary gland and their abnormalities in breast cancer.     

Age and biorhythms of the histophysiologic indices of the thyroid gland

Rhythmic changes of several histophysiological parameters of the thyroid gland was studied in 144 A/He mice of three age groups: young immature, mature adults and ageing animals. The multicomponent nature of the rhythmic changes was found for each index; it included the circadian component, as well as infradian oscillations. The leading role of the circadian component in the establishment of the biorhythms of the organ functioning was shown, whereas ontogenetic changes were chiefly associated with the ultradian components' attenuation.     

Effect of emotional-algesic stress on the hormonal function of thyroid and parathyroid glands

Experiments on 215 Wistar rats have revealed that the state of the endured stress is an essential factor inducing disturbance in functioning of the hypothalamus-adenohypophysis-thyroid gland system accompanied by disturbance in regulation of the thyrotropin and triiodothyronine formation under conditions of myocardium necrosis development.     

State of the capillary network of rat myocardium in the presence of hypertrophy and physical loading

Morphofunctional state of the capillary network in various myocardial parts was studied in white rats under normal conditions, myocardial hypertrophy of different degree and under physical loading. It was demonstrated that density, metabolic surface and capacity of the capillary bed is larger in the right ventricle than in the left one. The capillary blood supply in hypertrophied myocardium, increasing simultaneously with hypertrophy, at the state of rest corresponds to its increasing mass. On the contrary, under maximal physical loading functioning of the capillary part in the myocardium becomes unadequate that is evident from a decreasing activity of the test animals.     

The development and functioning of embryonic pancreatic islet cells in the anterior chamber of rats

In the present study the morphogenesis and differentiation processes in embryonic pancreatic gland implants into Wistar line rat anterior eye chamber have been investigated. The conditions therein were found to be favourable for the endocrine tissue functioning; a number of morphogenetic changes resulting in the formation of islet structure acting as a morphophysiological unit were noted as well. Endocrine cells possess some selective properties as compared to the exocrine tissue. Alloxan diabetic animals demonstrated the most optimum conditions for the endocrine cells development and functioning.     

Microscopic anatomy of the orbital Harderian gland in the common tree shrew (Tupaia glis)

The orbital Harderian gland of the common tree shrew (Tupaia glis) was investigated at the macroscopic and microscopic levels. In the glands of both sexes only one acinar cell type was found. The cell is characterized by the presence of numerous lipid vacuoles of variable size and by a small number of PAS-positive, electron-dense granules distributed throughout the cytoplasm, which are predominant at the basal portion of each acinar cell. The duct system is well developed within the gland. The content of lipid vacuoles within the acinar cells is secreted from the apical portions by exocytosis, indicating the exocrine function of the organ. Apart from the lipid vacuoles, both acinar and ductal luminal contents of the Harderian gland also contain accretion of electron-dense materials. The vascularization within the Harderian gland is unique in that two capillary types (small fenestrated and irregular sinusoidal capillaries) could be demonstrated. The presence of fenestrated capillaries together with other morphological features (such as accumulation of the small electron-dense granules at the basal pole and the presence of basolateral microvilli) near the basal portion of the acinar cells suggest that the Harderian gland in T. glis might also be involved in an endocrine function.     

Compensatory-restorative processes of the thyroid gland in 1- and 3-month-old rats in health and in desympathization

In 172 white male rats 1- and 3-month-old, using electron microscopical, autoradiographical, morphometrical and radioimmunological methods, analysis of structural-functional changes of the thyroid gland has been carried out both under normal conditions and at guanethidine desympathization (15 mg/kg for 14 days after birth). Resection of 2/3 of the organ has been performed on the 3d, 5th, 7th and 15th days before sacrifice. In the 1-month-old desympathized rats hypofunctional state of the gland is observed. By the 3d month at the expense of an increased production of thyrotropin and calcitonin the thyroid status becomes normal. The dynamics of the restorative processes in the thyroid gland after resection of 1/3 of the organ in the control and test rats occurs with a similar intensity. Proliferative potency of the desympathized thyroid tissue is much higher.     

Morphometric study of the blood-carrying capillaries during the administration of a liquid into the salivary gland]

The physiological saline was injected into the excretory duct of the cat parotid gland under the pressure of 30, 70 and 120 cm H2O. It was found with the aid of transmission electronic microscopy, morphometry and statistical analysis that the liquid injection into the gland produces compression of the blood capillaries weaving the acinus. The compression of the capillary tubes is shown by a significant reduction in space given to the lumen of the capillaries and their endothelial layer. The compression of the capillary tubes is combined with a two-fold lessening suggest that the additional blood volume entering the gland in response to its perfusion by the liquid does not reach the blood capillaries and is thrown off into the vein vessels through the shunt communications and that regulation of the blood volume getting into the cat parotid gland capillaries is likely to depend on the hydraulic and osmotic state in the interstitial space of glandular lobes.     

Observation on the composition and biosynthesis of egg wax lipids in the cattle tick,Boophilus microplus

The biosynthesis of wax lipids by Gené's organ, the egg waxing organ in ticks, was investigated. Gené's organ, a complex dermal gland system, applies a superficial wax layer to the eggs during oviposition which prevents desiccation and is essential for egg viability. The detailed anatomy and histology of the three gland cell types are unambiguously described. Serial sectioning of ticks showed that all three gland cell types are capable of contributing to the egg wax. The wax synthetic ability of these three gland types was characterized. The composition of wax lipids extracted from the surface egg wax, and from the three types of wax gland dissected from ovipositing ticks, was analysed using thin-layer and gas-liquid chromatography. Injection of ovipositing ticks with radiolabelled acetate resulted in the incorporation of the label into wax lipids by gland cells of Gené's organ. The egg wax was a complex mixture of long-chain alkanes and fatty acid esters. The gland cells contained a greater proportion of shorter chain alkanes than were present in the egg surface wax. Some unsaturated long-chain fatty acids were present, and these were more abundant in the gland cells than in the surface wax of oviposited eggs, suggesting that oxidation occurs after oviposition. The results confirm that the tubular glands, acinar accessory glands and lobular glands of Gené's organ all contribute to the egg waxes, although the lipid components differed in relative abundance. The results are also consistent with alkane synthesis from fatty acids in Gené's organ by a chain-elongation-decarboxcylation pathway.     

Correlation between the organ blood flow, substrate absorption from blood, the activity of transport into mammary gland secretory cells and formation milk components in cow

Epithelial cells of mammary alveoles may he considered as a bioreactor that works being monitored by regulatory system maintaining balance between blood substrate supply and rate of macromolecular synthesis. In the trial performed on lactating cows assigned to feeding regimen with temporally altered level of nutrition, functioning of this system in the course of a transition period was studied. The earliest sign of adaptation was a decrease in volume blood flow through mammary gland provoking decline in uptake of water soluble substrates (glucose, amino N, P-hydroxybutyrate) with increase in arterio-venous difference across mammary gland and extraction efficiency. At the end of deprivation period, an activity of transport into the cell decreased for amino N from 7.5 to 4.5; l/min (p < 0.05), for P-hydroxyhutyrate from 16.0 to 13.8 l/min; activity of glucose transport was not changed. The data obtained indicate existence of defined points in the system monitoring organ blood supply and transport of substrates into the cell being adjusted during adaptation to alteration in the level of nutrition.     

Potential role of autophagy in behavioral changes of the flank organ

The flank organ of the Syrian hamster, which shows a biodynamic response to androgen stimulation, is considered a good model for studying the androgen effect on sebaceous gland and hair. This organ is susceptible to programmed cell death (PCD), a prominent feature associated with sexual organ adjustment. We have recently shown the first direct evidence of a relationship between autophagy and morphological changes in androgen-dependent organs. In this work, animals were stabulated (housed) for two months under control conditions and, after sacrifice, autophagy markers, Beclin 1 and LC3-II, were evaluated. The results revealed autophagic processes in the flank organ of both sexes, especially in females, and no detectable caspase-3 activity. Therefore, these data indicated that macroautophagy, and not apoptosis, was the main mechanism by which the flank organ responds to androgen. Here, we present additional data on the flank organ, showing that the intensity of autophagy between genders depends on the length of stabulation. These data could indicate a role for autophagy in response to behavioral influences. A possible explanation and its implication in Syrian hamster social defeat are discussed in this addendum.     

Effects of Castration on Growth and Reproduction of Helisoma duryi (Mollusca: Pulmonata)

Summary

Castration of Helisoma duryi disturbs the balance between growth and reproduction in favour of growth, as is evidenced by the stimulation of body and shell growth and reduction in egg mass production when compared with sham operated controls. Female accessory sex organ wet weight is increased in castrated and virgin snails. Male accessory sex organ wet weight is unaffected and female accessory sex organ wet weight is reduced by dorsal body ablation, suggesting that growth of differentiated female accessory sex organs is stimulated by the endocrine dorsal bodies. Albumen gland synthetic activity is inhibited in the absence of a functioning gonad. This inhibition may be due partly to the accumulation of secretory products within the glands and partly to the inactivation of the endocrine dorsal bodies and neurosecretory caudodorsal cells in the cerebral ganglia. The circulating levels of the vitellogenic protein ferritin are reduced by castration, and increased by injection and implantation of active gonadal tissue into castrates. This may be due to an indirect effect of gonadal factor (s) on the extragonadal synthesis of ferritin.     

The capillary system of the rat heart in occlusion of the coronary artery

In 74 white rats by means of non-injection++ method morphofunctional state of the myocardial capillary bed has been studied in dynamics at occlusion of descending branch of the left coronary artery. During the first week after the operation blood supply of the areas, adjoining the necrosis, increases at the expense of dilatation and some increase in number of functioning capillaries, that results in enlargement of the exchanging surface and capacity of the capillary bed. Beginning from the 12th day, the value of all these parameters decreases, however, they do not reach their initial level. By the end of the experiment (45 days) the number of the functioning capillaries somewhat decreases, but the capillary diameters remain increased. By that time in the myocardial areas, adjoining the necrosis a parviansiform capillary network without a definite orientation, concerning muscle fibers, has been formed.