Vol 47, No 2 (2016)
- Year: 2016
- Articles: 6
- URL: https://journals.rcsi.science/1062-3604/issue/view/11465
Mechanisms of Normal and Pathological Tissue Development
Connective tissue growth factor (CTGF) in the human dermis through ontogenesis
Abstract
Connective tissue growth factor (CTGF) was examined in the structures of dermis of humans with different ages, from 20 weeks of pregnancy to 85 years. By immunohistochemistry, the fibroblasts and blood vessels positively stained for CTGF were observed in the dermis of all examined ages. An age-dependent increase in the percent of the fibroblasts and blood vessels positively stained for CTGF in the dermis was observed. A statistically significant negative correlation was found between the age-dependent changes in the total number of fibroblasts, percent of the fibroblasts with positive staining for proliferating cell nuclear antigen, and portion of the fibroblasts with positive staining for CTGF. Another statistically significant negative correlation was found between the age-dependent changes in the number of blood vessels and portion of the blood vessels with a positive staining for CTGF. The results suggest that CTGF has an inhibitory influence on the angiogenesis and fibroblast renewal in the human dermis through ontogenesis.
Excess of exogenous nitrates inhibits formation of abnormal wood in the Karelian birch
Abstract
The effect of exogenous nitrate on the sucrose-metabolizing enzyme activities—sucrose synthase (SS) and apoplastic invertase (ApInv)—in the xylem and phloem of the silver (Betula pendula Roth var. pendula) and Karelian (B. pendula var. carelica) birches (the latter is well known for its abnormal, patterned wood) has been studied. A stable correlation between the enzyme activities and deviations in the growth and development of stem vascular tissues during cambial growth has been demonstrated. Formation of the birch wood with a common structure is associated with high SS activity. In this case, the reaction yields UDP glucose, which is utilized mainly for synthesis of the cell wall components of vessels and fiber tracheids. As for the Karelian birch, the SS activity in the xylem formation zone is decreased, which complies with a higher sucrose level in the tissue. The excess sucrose is released into the apoplast to be cleaved by ApInv. The resulting hexoses induce storage metabolism, thereby increasing the amount of storage substances and the share of storage parenchyma cells in the xylem. As a result, the Karelian birch wood acquires large inclusions in the parenchyma, which render a characteristic pattern. A change in the ratio of SS to ApInv activities underlies a great variety in the degree of wood patterning observed in Karelian birch trees. In the common silver birch, the nitrate application increases the sucrose utilization via SS pathway, which results in an increase in wood growth. In the Karelian birch xylem, nitrates lead to a decrease in both the SS (a decrease in wood growth) and ApInv (a decrease in the amount of parenchyma, i.e., normalization of the wood structure). The sucrose metabolizing in the xylem decreases on the background of an increase in its utilization in the phloem, where both enzyme activities elevate. It is assumed that the fact that the Karelian birch distribution range is limited by rich soils can be determined by a shift from intensive apoplastic sucrose utilization zone towards the phloem caused by high doses of nitrogen nutrition.
Developmental Cytology
Dopamine disorganizes direct intercellular interactions in keratinocytes cultures: A comparison to hepatocytes
Abstract
Dopamine in the concentration 0.4 μg/mL abolishes protein synthesis rhythm in HaCaT keratinocytes and hepatocytes unlike noradrenaline or melatonin, which synchronize direct intercellular interactions and organize protein synthesis rhythm. Experiments with D2 dopamine receptors blocking agent metoclopramide (tserukal) in the concentration 2 μg/mL show that a disorganizing effect of dopamine is driven by the activation of D2 receptors, which block adenylyl cyclase and the efflux of calcium ions from internal depos according to the literature. It is shown that tserukal does not activate serotonin receptors in our experimental settings. Cellular interactions’ recovery during or after dopamine action is carried out by melatonin in the concentration 0.001 μg/mL. A recommendation to inject melatonin before dopamine administration for different medical indications is discussed.
Regeneration
High regenerative ability of tailed amphibians (Urodela) as a result of the expression of juvenile traits by mature animals
Abstract
The highest potencies of regeneration in tailed amphibians in comparison with the abilities of organ and tissue restoration in other vertebrates represent the goal of longstanding and intense studies. Accumulated information can half-open some mysteries of cellular and molecular fundamentals of regeneration in Urodela, but it does not explain the maintenance of regenerative abilities in mature, adult animals. The information summarized in the review suggests that the paedomorphosis inherent in this animal group determines the keeping of the juvenile state on all levels of organization—from organismic to molecular. This, in turn, permits and eases initiation and development of regenerative responses to trauma, right up to the epimorphic regeneration of whole organs. As an example, we have traced paedomorphosis-associated cellular and molecular specificities of urodelean eye and brain tissues, which could possibly play a permissive role in their complete regeneration.
Morphogenesis
Influence of surfagon on rheoreaction of juvenile rainbow trout
Abstract
The rheoreaction of juvenile rainbow trout (aged 2 months) was studied 30–40 days after a single injection of surfagon (synthetic analogue of gonadotropin-releasing hormone). Individuals subjected to surfagon preferred to move against the water current both in normal and migratory state, while control (not injected) individuals preferred to move downstream. Surfagon strongly modified the rheoreaction of individuals in normal and migratory state.
Embryogenesis and Carcinogenesis
Hypoxia during mammalian preimplantation development: Extreme circumstance vs. typical environment
Abstract
The given paper summarizes the data on the early mammalian embryo development in culture media containing low oxygen concentration. Experimental results on in vitro modeling the hypoxia for preimplantation development are reviewed. Hypoxic conditions were shown to be available in the female reproductive tract of different mammalian species. The estimation of the embryo developing in vitro exhibits that lower oxygen level in culture media improves embryonic quality.