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

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.

2020 ◽  
pp. 23-27
Author(s):  
В. В. Елагин ◽  
Д. А. Костина ◽  
О. И. Братчиков ◽  
Т. Г. Покровская ◽  
С. Л. Кузнецов ◽  
...  

Цель - выявить и изучить степень выраженности морфологических изменений структур коркового и мозгового вещества почки на фоне смоделированной билатеральной модели ишемии-реперфузии. Материал и методы. Эксперименты проведены на 50 крысах-самцах линии Вистар массой 180-220 г. Моделирование билатеральной модели ишемии-реперфузии проводилось путем наложения атравматичных зажимов на обе почечные ножки на 40 мин. Через 24 или 72 ч реперфузии проводили оценку выраженности структурных изменений в корковом и мозговом веществе почки с использованием гистологических и морфометрических методик. Измеряли высоту эпителиоцитов в проксимальном и дистальном извитых канальцах нефрона, площадь поперечного сечения почечного тельца, клубочка и капсулярного пространства. Результаты. Полученные морфологические изменения в виде нарушения структурности эпителия как в корковом, так и в мозговом веществе почки на 1-е сутки эксперимента имеют тенденцию к увеличению степени их выраженности. К 3-м суткам эксперимента наиболее выраженные реактивно-деструктивные изменения визуализируются в реабсорбционносекреторных отделах нефрона, которые проявляются в виде снижения высоты эпителиоцитов проксимальных и дистальных канальцев, отслоением их от базальной мембраны и слущиванием. Усугубление схожей морфологической картины происходило в собирательных трубках, в просветах которых определялись конгломераты из отслоившихся от базальной мембраны погибших клеток эпителия. Выявленные реактивно-деструктивные изменения в почках морфологически обосновывают адекватность создания модели ишемии-реперфузии. Выводы. 40-минутная билатеральная ишемия почек с последующей реперфузией в течение 1-3 сут приводит к выраженным структурным изменениям в почках, что соответствует характеристике острого почечного повреждения. Objective - to identify and study the severity of morphological changes in the structures of the renal cortex and medulla in the bilateral model of ischemia-reperfusion. Material and methods. The experiments were performed on 50 male Wistar rats weighing 180-220 grams. A bilateral ischemia-reperfusion was modelled by applying atraumatic clamps to both kidney pedicles for 40 minutes. After 24 or 72 hours of reperfusion, the severity of structural changes in the renal cortex and medulla was assessed using histological and morphometric techniques. The height of epithelial cells in the proximal and distal convoluted tubules of the nephron, the cross-sectional area of the renal corpuscle, glomerulus and capsular space were measured. Results. Severe structural changes in the renal tissue affecting both the tubular and glomerular apparatus of the kidneys were found, with the increase in pathological changes from the first to the third days of the experiment in the form of a decrease in the epithelial height of the distal and proximal tubules, as well as a decrease in the area of the renal corpuscle and vascular glomerulus. The morphological changes in the form of a structural damage of the epithelium of both renal cortex and medulla were detected on the 1st day of the experiment, and they tend to increase their severity. By the 3rd day of the experiment, the most pronounced reactive-destructive changes were visualized in the reabsorption-secretory sections of the nephron. They were manifested as a decrease in the height of the proximal and distal tubule epithelial cells, their exfoliation from the basement membrane and desquamation. The similar but more aggravated morphological picture was seen in collecting tubes, where conglomerates of dead epithelial cells exfoliated from the basement membrane were found in the gaps. The revealed reactive-destructive changes in the kidneys morphologically substantiate the adequacy of creating a model of ischemia-reperfusion. Conclusions. A 40-minute bilateral renal ischemia followed by reperfusion leads to severe structural changes in the kidneys in 1-3 days, which corresponds to a characteristic of acute renal damage.


1982 ◽  
Vol 60 (10) ◽  
pp. 2367-2381 ◽  
Author(s):  
John H. Youson

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.


1974 ◽  
Vol 52 (12) ◽  
pp. 1447-1455 ◽  
Author(s):  
J. H. Youson ◽  
S. J. Hansen ◽  
I. M. Campbell

The length and cross-sectional area of the kidneys and the elongate renal corpuscles in both marine and freshwater lamprey, Petromyzon marinus L., increase proportionately as the animal increases in length. The paired kidneys are seldom identical, with one kidney usually longer and of greater cross-sectional area. Marine males demonstrate a larger cross-sectional area of their kidneys and renal corpuscles compared with marine females of similar size. The cross-sectional areas of the renal corpuscles of freshwater and marine animals are not significantly different and hence the amount of filtration surface is the same in the kidneys of both groups of animals. The evolution of the renal corpuscle and the involvement of this structure in osmoregulation in lampreys is discussed.


1979 ◽  
Vol 57 (1) ◽  
pp. 237-246 ◽  
Author(s):  
J. H. Youson ◽  
J. Lee ◽  
I. C. Potter

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.


2004 ◽  
Vol 118 (3) ◽  
pp. 611-619 ◽  
Author(s):  
Yu-Wen Chung-Davidson ◽  
Sang-Seon Yun ◽  
John Teeter ◽  
Weiming Li

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Un Chul Park ◽  
Eun Kyoung Lee ◽  
Bo Hee Kim ◽  
Baek-Lok Oh

AbstractIn this cross-sectional study, we investigated choroidal thickness (CT) and scleral thickness (ST) in highly myopic eyes and their associations with ocular factors. Patients underwent widefield swept-source optical coherence tomography (OCT) to measure the CT and ST at the subfovea and 3000 μm superior, inferior, temporal, and nasal to the fovea and macular curvature. A total of 237 eyes (154 patients) were included. At all five measurement points, thinner CTs and STs were associated with longer axial lengths (r = − 0.548 to − 0.357, all P < 0.001) and greater macular curvatures (r = − 0.542 to − 0.305, all P < 0.001). The CT and ST were significantly thinner in eyes with posterior staphyloma than in those without at all measurement points (all P ≤ 0.006) but did not differ between eyes with the wide macular and narrow macular type of staphyloma. Eyes with myopic maculopathy of category ≥ 3 according to the International Meta-Analysis for Pathologic Myopia classification had significantly thinner CTs and STs than those with category ≤ 2 (all P ≤ 0.005). In highly myopic eyes, a decrease in the CT and ST was more pronounced in eyes with more structural changes, such as longer axial length, steeper macular curvature, and the presence of posterior staphyloma.


Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1157
Author(s):  
María D. Díaz-Barreda ◽  
Isabel Bartolomé-Sesé ◽  
Ana Boned-Murillo ◽  
Antonio Ferreras ◽  
Elvira Orduna-Hospital ◽  
...  

Background: We study the retinal function measured by macular integrity assessment microperimetry (MAIA) and structural changes assessed by scanning swept source optical coherence tomography (SS-OCT) between healthy individuals and patients undergoing pars plana vitrectomy (PPV) after rhegmatogenous retinal detachment (RRD). Methods: Cross-sectional study. Early Treatment Diabetic Retinopathy Study (ETDRS) grids were measured by SS-OCT and compared with the MAIA parameters. Results: Thirty-eight eyes with RRD (19 macula-on and 19 macula-off) were compared with 113 healthy eyes. The retinal sensitivity and average total threshold were reduced in all sectors in the RRD group; macular integrity index was increased. Macular thicknesses in total retina and ganglion cell layer (GCL)++ protocols were higher in the RRD group in nasal outer (NO) and central (C) sectors and only in C sector for GCL+ protocol. Thicknesses were lower in total retina, GCL++ protocols in the temporal outer (TO) sector and in the GCL+ protocol in NO sector. Best-corrected visual acuity (BCVA) correlated moderately with retinal sensitivity in all sectors and in just several sectors with time between the date of surgery and the test. The central nasal (CN) sector thickness and the average total threshold were higher in the macula-on subgroup. Conclusions: RRD and subsequent surgery results in functional and structural changes, especially in individuals with macular detachment.


Author(s):  
Paulo Roberto Arruda Zantut ◽  
Mariana Matera Veras ◽  
Sarah Gomes Menezes Benevenutto ◽  
Angélica Mendonça Vaz Safatle ◽  
Ricardo Augusto Pecora ◽  
...  

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.


2020 ◽  
Vol 299 ◽  
pp. 113608
Author(s):  
Yu-Wen Chung-Davidson ◽  
Ugo Bussy ◽  
Skye Daniel Fissette ◽  
Weiming Li

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.

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


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