The morphology of the kidney in young adult anadromous sea lampreys, Petromyzon marinus L., adapted to seawater. II. Distal and collecting segments, the archinephric duct, and the intertubular tissue and blood vessels

1982 ◽  
Vol 60 (10) ◽  
pp. 2367-2381 ◽  
Author(s):  
John H. Youson
Keyword(s):  
Young Adult ◽  
Blood Vessels ◽  
Amorphous Material ◽  
Petromyzon Marinus ◽  
Small Diameter ◽  
Crystalline Material ◽  
Renal Tubules ◽  
Renal Cells ◽  
Morphological Transformation ◽  
Sea Lampreys

Gradual acclimation of young adult anadromous sea lampreys, Petromyzon marinus L., to full-strength (100%) seawater results in changes in the morphology of the distal and collecting segments, the archinephric duct, and the intertubular tissue and blood vessels. The alterations first appear in animals in 60% seawater and mainly are represented by a luminal precipitate in the distal and collecting segments and increased numbers of cytoplasmic granules in the cells of these segments. Luminal debris of degradating cells, concentric rings of an amorphous material, or a crystalline material is characteristic of distal segments from animals adapted to 80% seawater and it is accompanied by flattening of the epithelium and a further granulation and a vacuolation of the cytoplasm. The above features are present to a lesser extent in the collecting segment. In 100% seawater, further flattening, vacuolation, granulation, and apparent degeneration of distal cells occurs and there are many more small-diameter renal tubules. Granulation of endothelial cells of efferent arterioles in animals at concentrations of 80 and 100% may indicate that these cells are recruited to absorb macromolecules. The tubular interstitium at these two highest salinities possesses many cells involved in the phagocytosis of red blood cells. The morphological transformation of the renal cells indicates that young adult anadromous P. marinus may have some difficulty in osmoregulating in hyperosmotic environments.

The distribution of fat in larval, metamorphosing, and young adult anadromous sea lampreys, Petromyzon marinus L.

1979 ◽  
Vol 57 (1) ◽  
pp. 237-246 ◽  
Author(s):  
J. H. Youson ◽  
J. Lee ◽  
I. C. Potter
Keyword(s):  
Young Adult ◽  
Histological Study ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Body Cavity ◽  
The Body ◽  
Muscle Fibres ◽  
Sudan Black B ◽  
Long Duration ◽  
Sea Lampreys

A histological study using Sudan Black B has been made of the distribution and relative density of fat in the various regions of the body of larval (ammocoete), metamorphosing, and young adult stages of the anadromous sea lamprey, Petromyzon marinus L., caught in New Brunswick. The principal sites of fat storage are located in and around the fat column, lateral to the notochord, between the notochord and either the cardinal or caudal veins, surrounding the body cavity, beneath the skin, and in the myosepta and the nephric fold. Dense but more restricted sites are present lateral to the nerve cord, between the bundles of muscle fibres, and surrounding the pharyngeal cavity. Fat is most abundant in large ammocoetes captured in May and June and in those displaying the very earliest stages of metamorphosis in July. The amount of fat declines during metamorphosis, but is still abundant in November just prior to the time when the sea lamprey can commence parasitic feeding. Fat was undetectable, however, in nearly every site in those animals in which feeding was delayed until the following May. This study shows that sea lampreys accumulate large amounts of fat at the end of larval life by employing a wide variety of different storage sites. It also demonstrates that the fat in virtually all of these sites may be exhausted when the nontrophic period following the initiation of metamorphosis is of a very long duration.

The morphology of the kidney in young adult anadromous sea lampreys, Petromyzon marinus L., adapted to seawater. I. General morphology and fine structure of the renal corpuscle and the proximal segments

1982 ◽  
Vol 60 (10) ◽  
pp. 2351-2366 ◽  
Author(s):  
John H. Youson
Keyword(s):  
Young Adult ◽  
Structural Changes ◽  
Petromyzon Marinus ◽  
Cross Sectional ◽  
Renal Corpuscle ◽  
Sea Lampreys ◽  
Lateral Intercellular Spaces ◽  
Pars Recta ◽  
Seawater Acclimation ◽  
Pars Convoluta

The morphology of the opisthonephric kidney of young adult anadromous sea lampreys, Petromyzon marinus L., was examined at regular intervals during the gradual acclimation of these recently metamorphosed individuals to full-strength seawater. No alteration of the renal corpuscle, the ciliated neck segment, or the proximal pars convoluta and pars recta segments is observed through 40% seawater, but dilation of ventral tubules, the accumulation of a white precipitate, and specific fine structural changes in the cells of the proximal segments are noted in 60% seawater. The ultrastructural alterations are more conspicuous in 80 and 100% seawater and may reflect the involvement of the proximal segment in secretion, likely magnesium and sulphate ions. Flattening of the epithelium in proximal segments, enlargement of lateral intercellular spaces in the recta segment, and apparent increases in numbers of intermediate segments at levels of 80% seawater is more obvious in animals adapted to 100% seawater. The smaller cross-sectional area of the renal corpuscle in animals adapted to 80 and 100% seawater compared with the area in lower salinity might explain the previously found reduced glomerular filtration rate which accompanies seawater acclimation in anadromous lampreys.

Brain Pathways and Behavioral Responses to Weak Electric Fields in Parasitic Sea Lampreys (Petromyzon marinus).

2004 ◽  
Vol 118 (3) ◽  
pp. 611-619 ◽  
Author(s):  
Yu-Wen Chung-Davidson ◽  
Sang-Seon Yun ◽  
John Teeter ◽  
Weiming Li
Keyword(s):  
Electric Fields ◽  
Petromyzon Marinus ◽  
Behavioral Responses ◽  
Sea Lampreys ◽  
Brain Pathways

scholarly journals Impact of Thermal Oxidation on Morphological, Structural and Magnetic Properties of Fe-Ni Wire-Like Nanochains

2021 ◽  
Author(s):  
Marcin Krajewski ◽  
Mateusz Tokarczyk ◽  
Sabina Lewińska ◽  
Kamil Bochenek ◽  
Anna Ślawska-Waniewska
Keyword(s):  
Magnetic Properties ◽  
Thermal Oxidation ◽  
Amorphous Material ◽  
Crystalline Material ◽  
Future Application ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Structural And Magnetic Properties ◽  
Source Of Information ◽  
The Magnetic Field

AbstractThis work presents the evolution of morphological, structural and magnetic properties of amorphous Fe-Ni wire-like nanochains caused by thermal oxidation. The initial Fe1−xNix samples (x = 0.75; 0.50; 0.25) were prepared through the magnetic-field-induced synthesis, and then they were heated in dry air at 400 °C and 500 °C. These treatments led to two competing simultaneous processes occurring in the investigated samples, i.e., (i) a conversion of amorphous material into crystalline material, and (ii) their oxidation. Both of them strictly affected the morphological and structural properties of the Fe-Ni nanochains which, in turn, were associated with the amount of iron in material. It was found that the Fe0.75Ni0.25 and Fe0.50Ni0.50 nanochains were covered during thermal treatment by the nanoparticle oxides. This coverage did not constitute a good barrier against oxidation, and these samples became more oxidized than the Fe0.25Ni0.75 sample which was covered by oxide nanosheets and contained additional Ni3B phase. The specific morphological evolutions of the Fe-Ni nanochains also influenced their saturation magnetizations, whereas their coercivities did not vary significantly. The obtained results constitute an important source of information for future application of the thermally treated Fe-Ni nanochains which could be applied in the energy storage devices or catalysis.

Sex-dependent pheromonal effects on steroid hormone levels in sea lampreys (Petromyzon marinus)

2020 ◽  
Vol 299 ◽  
pp. 113608
Author(s):  
Yu-Wen Chung-Davidson ◽  
Ugo Bussy ◽  
Skye Daniel Fissette ◽  
Weiming Li
Keyword(s):  
Steroid Hormone ◽  
Petromyzon Marinus ◽  
Hormone Levels ◽  
Sea Lampreys

Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Petromyzon Marinus ◽  
Attachment Site ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Oral Disc ◽  
Field Assessment ◽  
Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

Seasonal growth and duration of the parasitic life stage of the landlocked sea lamprey (Petromyzon marinus)

1995 ◽  
Vol 52 (6) ◽  
pp. 1257-1264 ◽  
Author(s):  
Roger A. Bergstedt ◽  
William D. Swink
Keyword(s):  
Seasonal Pattern ◽  
Life Stage ◽  
Petromyzon Marinus ◽  
Biomass Accumulation ◽  
Sea Lamprey ◽  
Gonadal Development ◽  
Adult Size ◽  
Sea Lampreys ◽  
Mean Size ◽  
Host Mortality

We used lengths and weights of 2367 live parasitic-phase sea lampreys (Petromyzon marinus) collected from Lake Huron, 1984–1990, to calculate their mean size at half-month intervals. Growth in weight was linear during June through September; increments averaged 11.1 g per half month. Growth increased sharply in October to several times the summer rate. We speculate that the increase in growth in October is explained partly by water temperature and partly by an increase in appetite related to the onset of gonadal development. The greater compression of biomass accumulation in autumn than has been previously demonstrated better explains the autumn pulse of sea lamprey induced host mortality. Based on the seasonal pattern of growth and on recaptures of marked sea lampreys, we conclude that landlocked individuals grow to adult size and mature in one parasitic growth year. Regressions of weight (grams) on total length (millimetres) differed significantly among months, and the season of collection must be considered in predicting weight from length.

Distribution of lamprey gonadotropin-releasing hormone in the brain and pituitary gland of larval, metamorphic, and adult sea lampreys, Petromyzon marinus

1994 ◽  
Vol 72 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Glenda M. Wright ◽  
Kim M. McBurney ◽  
John H. Youson ◽  
Stacia A. Sower
Keyword(s):  
Pituitary Gland ◽  
Preoptic Area ◽  
Petromyzon Marinus ◽  
Gonadotropin Releasing Hormone ◽  
Immunoperoxidase Technique ◽  
Dorsal Region ◽  
Releasing Hormone ◽  
Sea Lampreys ◽  
The Brain

Lamprey gonadotropin-releasing hormone was demonstrated in the brains of larval, metamorphic, and adult sea lampreys, Petromyzon marinus, using an immunoperoxidase technique. Gonadotropin-releasing hormone was observed in the neurohypophysis and preoptic area of the brain of larval, metamorphic, juvenile, and prespawning adults. The occurrence of immunoreactive cells and the intensity of the immunostaining was lowest in larvae, but by stage 5 of metamorphosis there was a marked increase in the prevalence and staining of these cells, which continued into adults. In larvae and lampreys in metamorphic stages 1–4, most immunoreactive fibres were confined to the dorsal region of the neurohypophysis. During stage 5 there was an expansion of immunopositive fibres into the ventral portion of the neurohypophysis. Prominent immunoreactivity was observed throughout the neurohypophysis from stage 5 onward through the adult stages. Changes in immunoreactivity of these cells and fibres in the brain and neurohypophysis correlate well with increased concentrations of hormone in the brain during development and with the timing of presumed changes in activity of cells in the adenohypophysis during metamorphosis.

Scaffolds in tissue engineering of blood vessels

2010 ◽  
Vol 88 (9) ◽  
pp. 855-873 ◽  
Author(s):  
Divya Pankajakshan ◽  
Devendra K. Agrawal
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Blood Vessels ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Biological Scaffolds ◽  
Hemodynamic Forces ◽  
Biodegradable Scaffolds

Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.

Mechanism of the Crystallization of High Polymers

1954 ◽  
Vol 27 (2) ◽  
pp. 374-384 ◽  
Author(s):  
G. Schuur
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Amorphous Material ◽  
Crystalline Polymer ◽  
Longitudinal Direction ◽  
Crystalline Material ◽  
Current View ◽  
X Ray ◽  
Made In ◽  
High Polymers

Abstract The crystallization of higher polymers is a phenomenon which is not yet fully understood, one of the main difficulties being to explain how the spherulites arise. An attempt will be made in this paper to draw a clearer picture of the mechanism of crystallization and thus to account for the origin of spherulites. It will then be seen how several other phenomena involved in the crystallization of natural rubber can be shown to be logically interrelated. The current view is that a crystalline polymer consists of a continuous amorphous phase containing small crystalline regions, the crystallites. The evidence as to the size of these crystallites, however, is at present inconclusive, because only the lower limit of their size can be measured by means of x-ray examination. The reason is that, owing to the absence of reflections of a higher order, the effect of irregularities in the crystallites and of the heat motion of the molecules cannot be measured separately. Another doubtful question is whether the small angle interference maxima are to be interpreted as a measure of mean distances between the crystallites. To do this, Wallner has to resort to the assumption that the crystallites are unstable, whereas it is presumed, on the evidence of the mechanical properties of the high polymers, that a crystallite is stable and permanent. Hoffmann found 82 ± 7 per cent of crystalline material in polychlorotrifluoroethylene and Buckley, Cross, and Ray found as much as 95 per cent in polymethylene. Such high percentages make it doubtful whether the crystalline phase can be discontinuous at all. In this article any volume of material in which the molecules lie parallel is called a crystallite. The direction in which the molecules are oriented is termed the longitudinal direction of the crystallite. It is immaterial to the argument whether a crystallite consists of several crystallites, aligned in parallel separated by a small amount of amorphous material, or of a single crystallite containing large irregularities.

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