Consequence Of Morphological Changes Research Articles

Dietary Biotin Supplementation Impairs Testis Morphology and Sperm Quality.

Supplements containing pharmacological concentrations of biotin are commercially available over the counter. Classical toxicity studies have considered biotin administration as harmless; however, recent investigations have shown that biotin supplementation modifies tissue morphology without changes in toxicity markers, raising concerns about the consequences of morphological changes on tissues' functions and the safety of pharmacological concentrations of the vitamin. Testes are very sensitive to toxicants, and testicular histology is a reliable method to study its function. In this work, we investigated the effects of dietary biotin supplementation on testis morphology and spermatogenesis function using an experimental model, in which we have not observed unfavorable effects on other tissue functions or toxicity markers. Male BALB/cAnNHsd mice were fed a control or a biotin-supplemented diet (1.76 or 97.7 mg biotin/kg diet) for 8 weeks. Compared to the control group, the biotin-supplemented mice presented remarkable testis morphology changes, including increased spermatogonia layers; the cellular mechanism involved is related to increased proliferation. Sperm count and serum testosterone levels were not affected, but spermatozoa motility and morphology were significantly impaired in the biotin-supplemented mice. These results caution against the use of supplements with high concentrations of biotin and indicate that biotin's pharmacological effects on morphology need to be considered in toxicological studies.

Photoelectrochemical water splitting with 600 keV N2+ ion irradiated BiVO4 and BiVO4/Au photoanodes

Low energy N2+ ion beam with 600 keV energy has been used to irradiate BiVO4 and Au nanoparticles loaded BiVO4 (BiVO4/Au) thin films deposited over fluorine doped tin oxide substrates via spray pyrolysis technique. Ion irradiation results in tailoring the optical, electrical, and morphological properties of the thin films and thence also responsible for changes in electrochemical properties. The scanning electron microscope images reveal the evolution of Au nanoparticles after irradiation at 2 × 1015 fluence to a nanourchins type of morphology. In consequence of morphological changes, the signature of surface plasmon resonance peak exhibited by Au nanoparticles in BiVO4/Au shows improvement. An increase of approximately 92% in photocurrent density in comparison to pristine BiVO4 has been found after irradiation in BiVO4/Au photoanode at 2 × 1015 ions/cm2 fluence. Moreover, irradiation also aids in improving photoelectrochemical response of BiVO4 photoanodes without Au nanoparticles. The enhancement can be attributed to the notable changes in onset potential, charge separation, charge transfer resistance and optical properties.

некоторые аспекты патогенеза вентральных грыж

Objective: To study some features of pathogenetic mechanisms of development of ventral hernias. Methods: The results of diagnostics and treatment of 140 patients with ventral hernias are analyzed. In 75 (53.6%) cases there were acquired hernias, and in 65 (46.4%) – postoperative cases. The size of the hernial protrusion of the latter is distributed as follows: giant (n = 12), large (n = 42), medium (n = 58) and small (n = 28). Results: To study the etiopathogenetic mechanisms of the origin of ventral hernias and their relapses in 60 (42.8%) observations of the parameters of lipid peroxidation (LPO) in the aponeurosis biopsy material and muscles with different sizes of hernial gates. Thus, the content of conjugated dienes and malonic dialdehyde in aponeurosis with large ventral hernia reached 1.7±0.07 μmol/mg and 3.5±0.03 μmol/mg, and in biopsies of rectus abdominal muscles 1.9±0.03 μmol/mg and 3.7±0.02 μmol/mg, respectively. The dependence between the content in the blood of the free hydroxyproline and the dimensions of a ventral hernia was noted. Thus, with small ventral hernias, these indices were 21.6±1.4 μmol/l, and for medium and large – 23.1±0.5 μmol/l and 24.2±1.1 μmol/l, respectively. Conclusion: When performing hernioplasty, it is advisable to excise the margins of the aponeurosis of the hernia gates zone, where there is a high content of LPO and the consequences of morphological changes, that allows reducing the frequency of relapse herniation development. Keywords: Ventral hernia, lipid peroxidation, relapse.

Fundamentals of translational neuroscience in toxicologic pathology: optimizing the value of animal data for human risk assessment.

A half-day Society of Toxicologic Pathology continuing education course on "Fundamentals of Translational Neuroscience in Toxicologic Pathology" presented some current major issues faced when extrapolating animal data regarding potential neurological consequences to assess potential human outcomes. Two talks reviewed functional-structural correlates in rodent and nonrodent mammalian brains needed to predict behavioral consequences of morphologic changes in discrete neural cell populations. The third lecture described practical steps for ensuring that specimens from rodent developmental neurotoxicity tests will be processed correctly to produce highly homologous sections. The fourth talk detailed demographic factors (e.g., species, strain, sex, and age); physiological traits (body composition, brain circulation, pharmacokinetic/pharmacodynamic patterns, etc.); and husbandry influences (e.g., group housing) known to alter the effects of neuroactive agents. The last presentation discussed the appearance, unknown functional effects, and potential relevance to humans of polyethylene glycol (PEG)-associated vacuoles within the choroid plexus epithelium of animals. Speakers provided real-world examples of challenges with data extrapolation among species or with study design considerations that may impact the interpretability of results. Translational neuroscience will be bolstered in the future as less invasive and/or more quantitative techniques are devised for linking overt functional deficits to subtle anatomic and chemical lesions.

The initial process of enamel prism arrangement and its relation to the Hunter-Schreger bands in dog teeth

The three-dimensional architecture of enamel prisms at early stages of enamel formation and its spatial relationship to the Hunter-Schreger bands were examined in canine tooth germs by light and electron microscopy. In serial semithin sections of demineralized tooth germs tangential to the enamel-dentin junction, a straight row of enamel prisms was depicted along the longitudinal tooth axis at the level of the enamel-dentin junction and then their three-dimensional arrangement was reconstructed using computer software. The spatial arrangement of the groups of enamel rods oriented in specific sideward directions was also reconstructed in deep layers of the enamel. Initially, all enamel prisms were parallel to perpendicular toward the enamel-dentin junction, but at 10µm from the enamel-dentin junction, some small specks, or groups of enamel prisms--tilting to the right or the left--emerged as small islands. In each speck of enamel prism, the inclined prisms were uniformly oriented in a sideward direction and gradually expanded their boundary until merging with the neighboring specks inclined in the same direction. Consequently, at 50µm from the enamel-dentin junction, the group of enamel prisms oriented either to the right or the left formed alternately arranged horizontal belt-like zones, corresponding to the parazone or the diazone of the Hunter-Schreger bands. Reversed images of scanning electron-micrographs of the exposed surfaces of the developing enamel revealed round and bulb-like profiles of Tomes' processes at early amelogenesis and its changes into a characteristic structure combined with flat secretory and enclosing nonsecretory faces that dictated the orientation of corresponding enamel prisms. The results suggest that the groups of enamel prisms oriented in sideward directions first appear as small island-like specks near the enamel-dentin junction, which later merge and form alternating horizontal belt-like zones as a consequence of morphological changes of the Tomes' processes. However, the mechanisms whereby the functional grouping of secretory ameloblasts with similarly oriented Tomes' processes is induced are yet to be determined.

ONTOGENETIC NICHE SHIFT IN THE BRACHIOPOD TEREBRATALIA TRANSVERSA: RELATIONSHIP BETWEEN THE LOSS OF ROTATION ABILITY AND ALLOMETRIC GROWTH

Abstract: Many articulated brachiopods experience marked life habit variations during ontogeny because they experience their fluid environment at successively higher Reynolds numbers, and they can change the configuration of their inhalant and exhalant flows as body size increases. We show that the extant brachiopod Terebratalia transversa undergoes a substantial ontogenetic change in reorientation governed by rotation around the pedicle. T. transversa′s reorientation angle (maximum ability to rotate on the pedicle) decreases during ontogeny, from 180 degrees in juveniles to 10–20 degrees in individuals exceeding 5 mm, to complete cessation of rotation in individuals larger than 10 mm. Rotation ability is substantially reduced after T. transversa achieves the adult lophophore configuration and preferred orientation with respect to ambient water currents at a length of 2.5–5 mm. We hypothesize that the rotation angle of T. transversa is determined mainly by the position of ventral and dorsal points of attachment of dorsal pedicle muscles relative to the pedicle. T. transversa shows a close correlation between the ontogenetic change in reorientation angle and ontogeny of morphological traits that are related to points of attachment of dorsal pedicle muscles, although other morphological features can also limit rotation in the adult stage. The major morphological change in cardinalia shape and the observed reduction of rotation affect individuals 2.5–10 mm in length. The position of ventral insertions of dorsal pedicle muscles remains constant, but contraction of dorsal pedicle muscles is functionally handicapped because dorsal insertions shift away from the valve midline, rise above the dorsal valve floor, and become limited by a wide cardinal process early in ontogeny (<5 mm). The rate of increase of cardinal process width and of distance between dorsal pedicle muscle scars substantially decreases in the subadult stage (5–10 mm), and most of the cardinalia shell traits grow nearly isometrically in the adult stage (>10 mm). T. transversa attains smaller shell length in crevices than on exposed substrates. The proportion of small‐sized individuals and population density is lower on exposed substrates than in crevices, indicating higher juvenile mortality on substrates prone to grazing and physical disturbance. The loss of reorientation ability can be a consequence of morphological changes that strengthen substrate attachment and maximize protection against biotic or physical disturbance (1) by minimizing torques around the pedicle axis and/or (2) by shifting energy investments into attachment strength at the expense of the cost involved in reorientation.

The evolution of cranial design and performance in squamates: Consequences of skull-bone reduction on feeding behavior

The evolution of cranial design in lepidosaurians is characterized by a general trend toward the loss of cranial elements. The evolution of relatively lighter skulls in squamates appears tightly coupled to a reduction in relative mass of the jaw adductor, implying functional consequences for bite force and feeding behavior. Interestingly, among squamates the postorbital bar was reduced or lost at least twice independently and taxa characterized by the loss of these cranial elements (e.g., geckos and varanids) are generally reported as having a mobile skull. In Gekkotans, the loss of the postorbital bar was accompanied by a reduction of the supratemporal bar, resulting in a pronounced cranial kinesis. Our data show that having a kinetic skull has functional consequences and results in a reduction in bite force. The lower bite force may in turn be responsible for the decreased feeding efficiency as reflected in the longer duration of intra-oral transport cycles. Gekkotans, however, appear to exploit their intracranial mobility in ways that increases the velocity of jaw movement during opening and closing, which may allow them to capture more elusive prey. The morphological changes observed in the evolution of the cranial system in squamates appear tightly linked to functional and constructional demands on the skull, making squamate skull evolution a model system to investigate the consequences of morphological changes in a complex integrated system of performance, behavior, and ecology.

Calycine colleters of seven species of Apocynaceae (Apocynoideae) from Brazil

The structure and organization of calycine colleters belonging to four genera of Apocynaceae are described. Calycine colleters were found in all species. All colleters had the same histological composition, but morphological differences were observed in four species. Most colleters were of the standard type, and possible deviations resulted in three morphological types: bifurcated, laminar, and sessile. Mechanisms of cell separation, proliferation, and elongation may explain the origin of the new types. As a consequence of morphological changes, the secretory surface was expanded in the bifurcated, laminar, and sessile glands. Most colleters were in a post-secretory phase, but a hydrophilic secretion was observed in Mandevilla pycnantha and Mesechites mansoana. A larger secretory surface, together with the extension of the secretory phase in adult flowers, were major shifts in the calycine colleters of Apocynaceae, and are possibly correlated with the functional and ecological aspects of these organs. Three patterns of distribution of calycine colleters were observed: alternate, opposite, or indefinitely distributed. The alternate pattern was not homogeneous, and three subtypes were recognized: four-, five-, and ten-grouped colleters. The number of calycine colleters was variable between taxa and even within the same species. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 152, 387–398.

Structure and mechanical properties of carbon?nickel and CNx?nickel nanocomposite films

DC sputtered carbon–nickel and carbon-nitride–nickel thin films were investigated by high resolution electron microscopy, X-ray microanalysis and nanoindentation to clarify the influence of Ni addition on the structure, formation and mechanical properties. The films were deposited in argon or nitrogen plasma at temperatures from 25 to 800 °C onto NaCl and SiO2 substrates. The microstructures can be described as nanocomposites, built from Ni/Ni3C nanocrystals in a carbon/CNx matrix. The mechanical properties of the films were found to be strongly dependent on the growth temperature along with the changes of the structure. The highest hardness of 14 GPa was measured for the film grown at 200 °C, while low values (down to 2–6 GPa) were obtained for films deposited at high temperatures. The decrease of the hardness is thought to be primarily the consequence of morphological changes of the crystalline phase. In films grown at room temperature and at 200 °C, an amorphous or nearly amorphous matrix was observed, while at higher temperatures up to 800 °C, the matrix showed relatively high ordering in the form of curved graphite/CNx layer stacks. At all temperatures above 200 °C, the Ni/Ni3C particles were encapsulated in three- to five-layer thick graphitic shells following exactly the surface of the Ni particles. TEM measurements confirm that nickel enhances the formation of ordered C/CNx structures as graphitic shells and fullerene-like domains in sputter-deposited films. Nanoindentation experiments show that the CNx–Ni films have slightly higher hardness compared to the C–Ni films.

Structure and mechanical properties of carbon–nickel and CN x–nickel nanocomposite films

DC sputtered carbon–nickel and carbon-nitride–nickel thin films were investigated by high resolution electron microscopy, X-ray microanalysis and nanoindentation to clarify the influence of Ni addition on the structure, formation and mechanical properties. The films were deposited in argon or nitrogen plasma at temperatures from 25 to 800 °C onto NaCl and SiO 2 substrates. The microstructures can be described as nanocomposites, built from Ni/Ni 3C nanocrystals in a carbon/CN x matrix. The mechanical properties of the films were found to be strongly dependent on the growth temperature along with the changes of the structure. The highest hardness of 14 GPa was measured for the film grown at 200 °C, while low values (down to 2–6 GPa) were obtained for films deposited at high temperatures. The decrease of the hardness is thought to be primarily the consequence of morphological changes of the crystalline phase. In films grown at room temperature and at 200 °C, an amorphous or nearly amorphous matrix was observed, while at higher temperatures up to 800 °C, the matrix showed relatively high ordering in the form of curved graphite/CN x layer stacks. At all temperatures above 200 °C, the Ni/Ni 3C particles were encapsulated in three- to five-layer thick graphitic shells following exactly the surface of the Ni particles. TEM measurements confirm that nickel enhances the formation of ordered C/CN x structures as graphitic shells and fullerene-like domains in sputter-deposited films. Nanoindentation experiments show that the CN x –Ni films have slightly higher hardness compared to the C–Ni films.

Relationship between song characters and morphology in New World pigeons

We studied the pattern of variation in song characters among 16 New World pigeon species belonging to different taxonomic groups defined by morphological characters. Structural, temporal and frequency characters of the song were analysed. Principal components analyses showed that species belonging to the same taxonomic group were also grouped together by their song characters. In addition, individuals were correctly assigned into taxonomic groups by discriminant function analyses in more than 87.8% of cases. These analyses also showed that more than 87.5% of the individuals could be correctly classified by species when all song characters were included. Correct classification of individuals by species and taxonomic groups dropped when character types were analysed separately, thus showing that structural, as well as temporal and frequency characters are fundamental to define species- and group-specific identities of New World pigeon's songs. Correspondence between patterns of vocal and morphological variation found in this study can be a consequence of evolutionary changes in morphology affecting song production, as for example body size changes that constrain the syrinx to produce certain acoustic frequencies.

Study of the initial stage of white rust formation on zinc single crystal by EIS, STM/AFM and SEM/EDS techniques

The kinetic consequences of morphological changes due to the zinc exchange process have been related to the corrosion performance and a further understanding of the initial stage of the white rust formation occurring preferentially in a thin layer of moisture in the absence of oxygen. Electrochemical impedance diagrams for a uniformly covered Zn corrosion product layer can be interpreted by a one-step dissolution mechanism, while on a non-uniform, partially active surface a consecutive dissolution occurs via adsorbed Zn(I) and Zn(II) species. The in situ EC-STM and EC-AFM observations revealed oriented Zn dissolution, deposition along the atomic steps and oriented oxide formation on the redeposited crystal planes in the early stages of each process.

STRUCTURE AND BEHAVIOR OF MULTICOMPONENT IMMISCIBLE POLYMER BLENDS

The morphology of ternary polypropylene (PP)-polyamine-6 (PA-6) glass (either beads [GB] or fibers [GF]) blends was investigated as a specific example of a multicomponent system. The implications of blend structure and filler partitioning on several properties, such as viscosity and crystallization behavior, are discussed. The morphology of multicomponent blends is predicted by the spreading coefficient, which is related to the interfacial tension between the various components. In ternary blends with a PA-6 matrix, the PP domains and glass filler are separately dispersed within the matrix. In ternary blends with a PP matrix, most of the PA-6 is found surrounding (encapsulating) the glass filler. The spreading coefficient was found to predict correctly the final morphology for most ternary blends studied, except for cases of kinetic hindrance, such as a high viscosity for one component. The spreading coefficient can also be used to predict the structure of four component blends. The different blend structures, encapsulation or separate dispersion of filler, affect the shear viscosity and its correspondence to a rule of mixtures prediction. For PA-6-rich blends (separate dispersion of filler), the actual viscosity is lower that the viscosity predicted by a proposed modified rule of mixtures. In PP-rich ternary blends (encapsulation of filler), however, the experimental viscosity data does match a modified rule of mixtures prediction. Dynamic rheological results for PP/PA-6 binary blends indicated that the blend dynamic viscosity increased with PA addition, whereas the shear viscosity results at high shear rates indicated a reduction in viscosity. The difference is a direct consequence of morphological changes during shear rheometry. Thermal results for the crystallization of PP in ternary PP/PA-6/GB blends with identical compositions but differing morphologies showed that the PP peak crystallization temperature and crystal size distribution were different in blends containing mainly a PP-glass interface (separately dispersed morphology) and those containing a PP-PA-6 interface (encapsulated morphology). In summary, the structure of multicomponent blends can be correlated with the rheological, mechanical, and thermal behavior of the blend. Filler segregation within one polymeric phase is strongly dependent on the surface characteristics of the polymers and the fillers.

Information spiraling: Movement of bacteria and their genes in streams

Bacteria in transport in streams are largely derived from other parts of the ecosystem. Here we review factors that influence transport of bacteria and their movement between habitats (such as sediment, water column, rocks, wood, and leaves) and consider the role of these movements in ecosystem processes. Bacteria enter the water column by sloughing, scouring, as a consequence of changes in morphology or hydrophobicity, or dislodgment by invertebrates and fish or other aquatic vertebrates. Transported cells (which may be planktonic or particle-associated) that colonize surfaces may establish new gene pools through cell division (vertical transfer) or genetic exchange (lateral transfer). Genetic information is also transported in streams as free or protected DNA or in bacteriophages. Movement of these vectors causes genetic information to spiral along a stream in a manner analogous to that of nutrients and organic carbon. Spiraling refers to the pattern of transport, uptake or attachment, and release of a molecule or cell. The flow of water in streams causes this cycle of attachment and release to be displaced downstream resulting in a spiral rather than a closed, stationary loop.

Functional elimination of afferent pathways and decreased safety factor during postembryonic development of cockroach giant interneurons.

The giant interneurons (GIN) from the cockroach CNS undergo two major physiological changes during the postembryonic developmental period: (A) a marked decrease in the number of afferent pathways innervating the GIN at the metathoracic ganglion (Ts); and (B) a gradual decrease in the safety factor for impulse propagation along the intraganglionic segment in T3. In 100% of the experiments (n greater than 100) performed on GIN from early developmental stages, spontaneous postsynaptic potentials (SPSPs) were recorded; in adults, on the other hand. SPSPs have been recorded in only 34% of the experiments (n = 74). Evoked synaptic potentials can be elicited in nymphal stages by stimulation of 8 nerves of T3, the contralateral connectives, ipsi- and contralateral nerve roots 2, 3, 5, and by stimulation of adjacent GINs. In adult, PSPs can be evoked by stimulation of adjacent GINs, and contralateral thoracic connectives, but not from nerves 2, 3 and 5. The functional disappearance of synaptic inputs to the GINs does not reflect a general phenomenon of reduction in synaptic transmission efficacy. In previous studies it was demonstrated that high frequency stimulation of adult GIN leads to blockage of impulse propagation in T3. In nymphal stages, the safety factor for propagation of impulses along T3 is higher. The reduction in safety factor appears gradually during the postembryonic developmental period. From analysis of the mechanisms underlying the elimination of functional afferent pathways and the appearance of low safety factor (see consecutive paper by Yarom and Spira) it is concluded that the functional elimination of afferents is a consequence of decreased transmission efficacy, while the appearance of low safety regions for impulse propagation is a consequence of morphological changes of the GIN segment within ganglion T3.

The effect of varying the polyethylene content and the co-polymer content on crazing in polystyrene?low-density polyethylene blends

The effect of varying the low-density polyethylene content and the polystyrenepolyethylene block co-polymer content on the rates of craze initiation and craze growth in polystyrene/low-density polyethylene blends has been studied. it was found that the parameters in the Eyring rate coefficients for craze initiation and craze growth are not dependent on the low-density polyethylene content. However, the rates of craze initiation increased with increasing low-density polyethylene content. This is explained tentatively by a new model for craze initiation. It is argued that effective crazes are only formed within clusters of low-density polyethylene particles that have overlapping stress-concentration fields. The dependence of the rate of craze initiation on the volume-fraction of dispersed phase that follows from this cluster model is qualitatively in agreement with experimental results. PS-PE co-polymer addition gives rise to changes in the Eyring parameters of the rate coefficients of craze initiation and craze growth. This may be a consequence of changes in morphology near the interface and of the different stress state at the interface.

Thy-1 cell surface antigen on cloned cell lines of the rat and mouse: Stimulation by cAMP and by butyrate

The level of the Thy-1 cell surface antigen on a number of established rat and mouse nerve cell lines can be stimulated by N 6, O 2′-dibutyryl adenosine 3′:5′-cyclic monophosphoric acid (Bt 2cAMP), in some cases up to the antigen level found in whole brain. On rat cell line BN1010-3, stimulation is also produced by phosphodiesterase inhibitors, adenosine 3′:5′-cyclic monophosphoric acid (cAMP) and its 8-bromo derivative, and l-isoproterenol. Hence, antigen elevation appears to occur via cAMP-related metabolism. It is not a consequence of morphological changes brought about by cAMP elevation in these cells, and is apparently independent of the inhibition of cell division by the nucleotide. Elevations of intracellular cAMP levels for at least one hour are needed to produce Thy-1 stimulation, after which an enhanced level of Thy-1 is observable after about 12 h. Continuous stimulation is required to maintain elevated antigen levels, for upon removal of the stimulating agent, the level of Thy-1 returns to the original unstimulated value within 48 h. Potent stimulation of the antigen level is also obtained with butyrate at 1–2 mM, which appears to be acting by a cAMP independent mechanism.