Structural changes in the zonulae occludentes of the chloride cells of young adult lampreys following acclimation to seawater

1991 ◽  
Vol 265 (3) ◽  
pp. 447-457 ◽  
Author(s):  
H. Bartels ◽  
I. C. Potter
Keyword(s):  
Young Adult ◽  
Structural Changes ◽  
Chloride Cells ◽  
Zonulae Occludentes

Structural changes in the apical membrane of lamprey chloride cells after acclimation to seawater

1993 ◽  
Vol 265 (3) ◽  
pp. C733-C739 ◽  
Author(s):  
H. Bartels ◽  
H. Schewe ◽  
I. C. Potter
Keyword(s):  
Structural Change ◽  
Young Adult ◽  
Diffraction Analysis ◽  
Structural Changes ◽  
Apical Membrane ◽  
Freeze Fracture ◽  
Optical Diffraction ◽  
Chloride Cells ◽  
Geotria Australis ◽  
Epithelial Membranes

Freeze-fracture replicas demonstrate that the apical membrane of the chloride cells of young adult lampreys (Geotria australis) undergoes a structural change when the animal is acclimated from freshwater to seawater. Although the particles on both the P face and the E face of this membrane are randomly distributed in freshwater animals, they are usually arranged in clusters on both fracture faces in seawater-acclimated animals. Light optical diffraction analysis demonstrates that the particles forming the clusters are periodically arranged. Although comparable clusters of particles have not been recorded in other epithelial membranes that are engaged in transporting ions into a hypertonic environment, they may be involved in the final step of Cl- secretion by the chloride cells of lampreys in seawater.

scholarly journals Lasting effects of prenatal exposure to Cannabis in the retina of the offspring: an experimental study in mice

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Paulo Roberto Arruda Zantut ◽  
Mariana Matera Veras ◽  
Sarah Gomes Menezes Benevenutto ◽  
Angélica Mendonça Vaz Safatle ◽  
Ricardo Augusto Pecora ◽  
...  
Keyword(s):  
Young Adult ◽  
Light Microscopy ◽  
Prenatal Exposure ◽  
Structural Changes ◽  
Volume Fraction ◽  
Clinical Care ◽  
Retinal Layer ◽  
Exposed Population ◽  
The Central Nervous System ◽  
The Impact

Abstract Background Prenatal exposure to Cannabis is a worldwide growing problem. Although retina is part of the central nervous system, the impact of maternal Cannabis use on the retinal development and its postnatal consequences remains unknown. As the prenatal period is potentially sensitive in the normal development of the retina, we hypothesized that recreational use of Cannabis during pregnancy may alter retina structure in the offspring. To test this, we developed a murine model that mimics human exposure in terms of dose and use. Methods Pregnant BalbC mice were exposed daily for 5 min to Cannabis smoke (0.2 g of Cannabis) or filtered air, from gestational day 5 to 18 (N = 10/group). After weaning period, pups were separated and examined weekly. On days 60, 120, 200, and 360 after birth, 10 pups from each group were randomly selected for Spectral Domain Optical Coherence Tomography (SD-OCT) analysis of the retina. All retina layers were measured and inner, outer, and total retina thickness were calculated. Other 37 mice from both groups were sacrificed on days 20, 60, and 360 for retinal stereology (total volume of the retina and volume fraction of each retinal layer) and light microscopy. Means and standard deviations were calculated and MANOVA was performed. Results The retina of animals which mother was exposed to Cannabis during gestation was 17% thinner on day 120 (young adult) than controls (P = 0.003) due to 21% thinning of the outer retina (P = 0.001). The offspring of mice from the exposed group presented thickening of the IS/OS in comparison to controls on day 200 (P < 0.001). In the volumetric analyzes by retinal stereology, the exposed mice presented transitory increase of the IS/OS total volume and volume fraction on day 60 (young adult) compared to controls (P = 0.008 and P = 0.035, respectively). On light microscopy, exposed mice presented thickening of the IS/OS on day 360 (adult) compared to controls (P = 0.03). Conclusion Gestational exposure to Cannabis smoke may cause structural changes in the retina of the offspring that return to normal on mice adulthood. These experimental evidences suggest that children and young adults whose mothers smoked Cannabis during pregnancy may require earlier and more frequent clinical care than the non-exposed population.

Labor Market Integration of Young Adult Refugees in Germany: Triangulating Perspectives Toward Program Development

2020 ◽  
Vol 30 (5) ◽  
pp. 553-563
Author(s):  
Sigrid James ◽  
Franziska A. Seidel ◽  
Juri Kilian ◽  
Julian Trostmann
Keyword(s):  
Labor Market ◽  
Young Adult ◽  
Program Development ◽  
Market Integration ◽  
Structural Changes ◽  
Formative Evaluation ◽  
Longitudinal Research ◽  
Qualitative Content Analysis ◽  
Outcome Data ◽  
Program Staff

This article reports on the 18-month formative evaluation of a model project aimed at preparing young adult refugees (YARs) for entry into vocational education training (VET) as an essential step toward the labor market. Qualitative methods were used to gain insight into the perspectives of YARs, program staff, and vocational instructors as well as explore program dynamics. Within a longitudinal research design, 45 qualitative semistructured interviews were conducted with 22 of 27 program participants. Additionally, program staff and vocational instructors were interviewed. Qualitative content analysis guided the analytic process. Outcome data indicated that 83.3% of program completers or 55.6% of the program participants entered a VET within the evaluation period. Triangulated qualitative data revealed relevant program processes and generated hypotheses about factors that facilitate or hinder the difficult transition for YARs. Implications for program development as well as needed structural changes are discussed.

Structural Changes in the Gills, Intestine, and Kidney of Etroplus maculatus (Teleostei) adapted to different Salinities

1961 ◽  
Vol s3-102 (59) ◽  
pp. 361-369
Author(s):  
V. VIRABHADRACHARI
Keyword(s):  
Structural Changes ◽  
Considerable Increase ◽  
High Salinity ◽  
Sea Water ◽  
Chloride Cells ◽  
Fresh Water Fish ◽  
Mucous Cells ◽  
Water Fish ◽  
Tunica Propria ◽  
Apical Vacuole

There is an increase in the number of the so-called ‘chloride cells’ in the gill epithelium with increasing salinity of the medium. In 75% and 100% sea-water the ‘chloride cells’ exhibit a change in structure, in that they become more granular and acquire an apical vacuole. There is also a general decrease in the number of mucous cells with increasing salinity of the medium of adaptation. The glomerulus tends to become smaller in the fishes adapted to high salinity as compared to the fresh-water fish. There is also a deposition of pigment around the nucleus and an indication of some changes in the nucleus of the kidney tubule cells in fishes adapted to 100% sea-water. In the intestine, adaptation to high salinities results in an increase in the nuclear size of the columnar epithelial cells, an increase in the number of flask-shaped cells, and a considerable increase in the thickness occupied by the tunica propria.

Electron paramagnetic resonance reveals age-related myosin structural changes in rat skeletal muscle fibers

2001 ◽  
Vol 280 (3) ◽  
pp. C540-C547 ◽  
Author(s):  
Dawn A. Lowe ◽  
Jack T. Surek ◽  
David D. Thomas ◽  
LaDora V. Thompson
Keyword(s):  
Skeletal Muscle ◽  
Electron Paramagnetic Resonance ◽  
Young Adult ◽  
Structural State ◽  
Structural Changes ◽  
Aged Rats ◽  
Paramagnetic Resonance ◽  
Specific Tension ◽  
Age Related ◽  
Electron Paramagnetic

We tested the hypothesis that low specific tension (force/cross-sectional area) in skeletal muscle from aged animals results from structural changes in myosin that occur with aging. Permeabilized semimembranosus fibers from young adult and aged rats were spin labeled site specifically at myosin SH1 (Cys-707). Electron paramagnetic resonance (EPR) was then used to resolve and quantify the structural states of the myosin head to determine the fraction of myosin heads in the strong-binding (force generating) structural state during maximal isometric contraction. Fibers from aged rats generated 27 ± 0.8% less specific tension than fibers from younger rats ( P < 0.001). EPR spectral analyses showed that, during contraction, 31.6 ± 2.1% of myosin heads were in the strong-binding structural state in fibers from young adult animals but only 22.1 ± 1.3% of myosin heads in fibers from aged animals were in that state ( P = 0.004). Biochemical assays indicated that the age-related change in myosin structure could be due to protein oxidation, as indicated by a decrease in the number of free cysteine residues. We conclude that myosin structural changes can provide a molecular explanation for age-related decline in skeletal muscle force generation.

Age-related structural changes in the young adult brain shown by magnetic resonance diffusion tensor imaging1

2005 ◽  
Vol 12 (3) ◽  
pp. 268-275 ◽  
Author(s):  
Takashi Yoshiura ◽  
Futoshi Mihara ◽  
Atsuo Tanaka ◽  
Osamu Togao ◽  
Takayuki Taniwaki ◽  
...  
Keyword(s):  
Young Adult ◽  
Magnetic Resonance ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Adult Brain ◽  
Age Related

Ion-secreting epithelia: chloride cells in the head region of Fundulus heteroclitus

1980 ◽  
Vol 238 (3) ◽  
pp. R185-R198 ◽  
Author(s):  
K. J. Karnaky
Keyword(s):  
Fundulus Heteroclitus ◽  
Chloride Transport ◽  
Basolateral Membrane ◽  
Freeze Fracture ◽  
Chloride Ion ◽  
Salt Gland ◽  
Chloride Cells ◽  
Head Region ◽  
Zonulae Occludentes ◽  
Apical Side

Transporting cells of ion-secreting epithelia are characterized by similar morphological patterns that include rich supplies of mitochondria, exotic patterns of surface amplification, and basolateral, plasma-membrane location of Na-K-ATPase, even though the direction of sodium transport across these epithelia is toward the apical side. Several new models for NaCl secretion propose that sodium, extruded into the intercellular space by Na-K-ATPase, reaches the apical side via the zonulae occludentes. Very recent freeze-fracture electron microscopy of avian salt gland and teleost chloride cells reveals that transporting cells are joined by simple, shallow zonulae occludentes. These observations lend morphological support to the concept that paracellular sodium ion permeation plays a central role in secretion. The chloride ion may traverse the epithelium via a transcellular route, entering the cell at the basolateral membrane by a chloride carrier linked to the cotransport of sodium down its electrochemical gradient into the cell. Finally, the chloride ion may exit the cell across the apical membrane by electrical forces. This review summarizes biochemical, morphological, and electrophysiological aspects of these new secretory models and the important contribution of a half century of research on teleost osmoregulatory mechanisms, including the chloride cell, to our understanding of sodium and chloride transport across secretory epithelia.

Fish Gill Structural Changes Induced by Toxicants and Other Irritants: A Statistical Review

1985 ◽  
Vol 42 (4) ◽  
pp. 630-648 ◽  
Author(s):  
Jon Mallatt
Keyword(s):  
Statistical Analysis ◽  
Epithelial Cells ◽  
Structural Changes ◽  
Defense Responses ◽  
Chloride Cells ◽  
Surrounding Water ◽  
Fish Gill ◽  
Ultrastructural Studies ◽  
Gill Lamellae ◽  
Exposure Conditions

Here I quantitatively review the literature on how fish gill morphology is affected by chemical and physical irritants in the surrounding water (e.g. various toxicants, extremes of temperature or pH). I catalogued histopathological gill lesions that were reported, and used statistics to explore how such lesions relate to the irritant-exposure conditions under which they occurred (specifically, to dose and class of irritant, to temperature, and to salinity of the surrounding water). Frequently recorded histopathologic lesions include changes in gill epithelium (lifting, necrosis, hyperplasia, hypertrophy, rupture), bulbing or fusing of gill lamellae, hypersecretion and proliferation of mucocytes, and changes in chloride cells and gill vasculature. I conclude that these lesions are largely nonspecific in nature, as each was detected under many different exposure conditions. The lesions are not entirely independent of exposure conditions, however, as my statistical analysis discerns these trends: (1) Most gill lesion types have been reported more frequently after lethal than after sublethal exposure to irritants. (2) Some lesions were more frequently detected in studies employing heavy metals than in studies using organic toxicants or other irritants; such lesions include necrosis and hypertrophy of gill epithelial cells, plus mucous hypersecretion. (3) Lifting of the branchial epithelium, the most commonly reported lesion, was reported more often in freshwater than in marine fish, suggesting that osmolarity of the ambient water influences this lesion. Little relation was found between recorded lesion frequencies and temperature. Following my statistical analysis, the etiology of irritant-induced gill lesions is considered. The nonspecificity of branchial alterations suggests that they primarily represent stereotyped physiological reactions of gills to stress, and many of them are logically considered defense responses. Some branchial alterations have been considered inflammatory, but I conclude that the literature cannot support that hypothesis. Ultrastructural studies have detected irritant-induced disruptions of branchial epithelial cells, including cytoplasmic vacuolization, autophagosomes and inclusions, loss of microvilli, and abnormal mitochondria and nuclei.

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.

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

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