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At least 19 recordsLinked to original sources

PubMed1992

Morphological characterization of exovesicles and endovesicles released from human erythrocytes following treatment with amphiphiles.

In order to morphologically characterize exo- and endovesicles released during treatment of erythrocytes with amphiphiles and to look for possible amphiphile-specific effects on the vesiculation pattern, human erythrocytes were treated at 37 degrees C with amphiphiles at concentrations where they exhibit maximum protection against hypotonic haemolysis (cAHmax). Released exo-and endovesicles and treated cells were studied by means of transmission (TEM) and scanning (SEM) electron microscopy. All sphero-echinocytogenic amphiphiles induced a release of both spherical and tubular exovesicles. Dodecyl maltoside, a nonionic amphiphile with a bulky polar head, induced a release of predominantly tubular exovesicles, while all other sphero-echinocytogenic amphiphiles induced a release of predominantly spherical exovesicles. Some branched tubular exovesicles were released by a double-chained cationic amphiphile. Tail- and tongue-like structures were often seen on the exovesicles. Spherical exovesicles were frequently invaginated. Stomatocytogenic amphiphiles induced endovesiculation. In erythrocytes treated with most of the stomatocytogenic amphiphiles the endovesicles were clustered, but with some amphiphiles the endovesicles were randomly distributed. Large ringformed endovesicles (octaethyleneglycol alkyl ethers) and endovesicles in chains (octyl and decyl glucopyranoside) also occurred. The endovesicle membrane was often budding onto the lumen of the vesicle and in some cases this could ultimately lead to a vesicle inside the endovesicle. We conclude that amphiphiles do not only trigger vesiculation, but may also specifically affect the vesiculation processes.

Erythrocyte Membrane↗

PubMed1991

CD3- leukocytes present in the human uterus during early placentation: phenotypic and morphologic characterization of the CD56++ population.

In this study, the CD3- LGL/NK cells present in the pregnant human uterus have been characterized. Phenotypic and morphologic analyses of decidual LGL revealed many similarities to the minor CD56bright+, CD16- subset in peripheral blood, but there were some important differences. The relative surface density of CD56+ is greatly increased on decidual LGL to 22x that found on the majority of CD56+ peripheral blood NK cells. The CD56bright+ cells in decidua show LGL morphology, whereas in peripheral blood, they are mainly agranular. Proliferation of CD56+ cells occurs predominantly during the nonpregnant secretory (luteal) phase, indicating these CD56+ uterine LGL do not migrate as terminally differentiated cells. The appearance of CD56+ cells was examined at the ultrastructural level using immunoelectron microscopy. Cells with phenotypic characteristics of decidual LGL occur in a higher percentage (1.11%) in the peripheral blood of women of reproductive age than in men (0.66%). On the basis of these results, it is proposed that the CD56bright+ uterine leukocytes represent a distinctive, hormonally regulated subset possibly adapted to control human placentation.

Adolescent↗

PubMed2026

Morphological characterization, genetic diversity and population structure of the rice blast pathogen Magnaporthe oryzae in Northeast India.

The blast pathogen, Magnaporthe oryzae, is one of the most destructive fungal pathogens of rice worldwide, yet its morphological features, genetic diversity and population structure in Northeast India remain poorly understood. In this study, twenty‒two M. oryzae isolates collected from eight states of Northeast India were characterized using morphological, molecular, and population genetic analyses. Morphological characterization revealed whitish to greyish‒white mycelia with sparse sporulation and colony diameters ranged from 36 to 90 mm, classifying the isolates into 14 fast and 8 slow‒growing groups. Whole genome sequencing was performed to enable both ITS‒based identification and SSR locus mining from the assembled genomes. Molecular identification using ITS rDNA sequences confirmed all isolates as M. oryzae, with 95.5-100% similarity. Phylogenetic analysis grouped the isolates into two major clades and identified seven ITS sequence types (GenBank Accessions: PX273287-PX273293). Genetic diversity assessed using 30 SSR markers revealed substantial polymorphism, with 1-7 alleles per locus and polymorphism information content (PIC) values ranging from 0.00 to 0.81. Heatmap clustering, dendrogram analysis, and distance metrics consistently identified two major genetic groups, with some isolates forming nearly identical clusters and others showing moderate divergence. Principal Component Analysis (PCA) and Principal Coordinates Analysis (PCoA) accounted for 87.8% of the total variance (PC1 and PC2 accounted for 54.4% and 33.4% respectively of the total variance) and revealed distinct outliers. Analysis of Molecular Variance (AMOVA) attributed 80% of the total genetic variation to differences among populations while only 20% was attributed to within population differences highlighting significant inter‒population divergence and clonal population structure. The study revealed substantial morphological and genetic diversity among M. oryzae populations in Northeast India, underscoring the need for region‒specific disease management strategies.

India↗

PubMed1991

Morphological characterization of a newly established human osteosarcoma cell line, HS-Os-1, revealing its distinct osteoblastic nature.

A newly established human osteosarcoma cell line, HS-Os-1, from an osteoblastic tumor arising in the left humerus of an 11-year-old girl was morphologically characterized in vitro and in vivo. HS-Os-1 cells in a monolayer have been maintained for more than 2 years since the initial cultivation, and were round or polygonal in shape with marked pleomorphism. Their cytoplasm was strongly positive for specific markers of osteoblasts, such as alkaline phosphatase and osteocalcin. Tumors induced in nude mice by HS-Os-1 cell inoculation at passage 12 or 23 revealed typical histological features of osteoblastic osteosarcoma, similar to those observed in the original tumor, producing prominent osteoid matrix with calcification. Ultrastructurally, HS-Os-1 cells in vitro and tumor cells in vivo showed similar well-developed, markedly dilated rough endoplasmic reticulum, polysomes and microfilaments in their cytoplasm. Additionally, many collagen fibers associated with deposition of electron-dense material were detected in the stroma featuring osteoid matrix. Thus, the HS-Os-1 cell line was shown to exhibit its osteoblastic nature in vitro and in vivo, and therefore might become an extremely useful tool for various pathomorphological investigations on human osteosarcomas.

Animals↗

PubMed1978

Biochemical and morphological characterization of subcellular fractions isolated from rabbit colon muscle.

From a homogenate of rabbit colon muscle subcellular fractions were isolated by differential centrifugation. The crude microsomal fraction could be separated into subfractions, a fraction of vesicular microsomes at 35% sucrose, a fraction containing sarcolemma, mitochondrial fragments and microsomal vesicles at 35--45% sucrose and a small protein fraction at 45--55% sucrose. Their biochemical properties and their morphological characterization were investigated. The cholesterol and the phospholipid content was equally distributed between the microsomal fractions 35% and 35--45% while the RNA was localized to the mitochondria and the microsomal fraction 35%. The enzyme cytochrome c oxidase was found to be concentrated in the mitochondria while a high contamination was found in the microsomal fractions 35--45%. The NADH-oxidase activity was highest in the 35% fraction and the 5'-nucleotidase activity in the 40,000 X g supernatant. The microsomal subfractions contained the enzymes ATPase, adenylate cyclase and phosphodiesterase. In the 35% fraction Ca stimulated the hydrolysis of ATP. The binding of [3H]-ouabain and the incorporation of [3H]-leucine was most pronounced in the 35% fraction. In a K+-free Krebs Ringer medium the binding of the glucoside was stimulated in all the fractions. From these results we concluded that the fraction 35% sucrose may be mainly derived from the endoplasmic reticulum and the plasma membrane while the 35--45% originates from the plasma membrane, mitochondria and to a lesser extent the endoplasmic reticulum.

Adenosine Triphosphatases↗

PubMed1979

Morphological characterization of slow and fast pyramidal tract cells in the cat.

In adult cats the morphology of slow and fast pyramidal tract (Pt) neurons was studied following intracellular HRP injections and Golgi impregnation. Both types of neurons are pyramidal cells and their soma are all located in the fifth layer of the motor area. As a rule, fast Pt neurons have large somata and their basal and apical dendrites occupy a larger territory in the tangential plane. In layer I, terminal apical dendrites of fast Pt neurons are smooth and divide poorly while those of slow Pt neurons bear a moderate amount of spines and branch profusely. Midway between the pia and layer V, in the third layer, the apical shafts of both types of Pt cells run upward with little branching. These shafts are more numerous in fast Pt cells (7 to 16) and they are almost devoid of spines. Those of slow Pt cells in layer III number between 5 and 9 and are densely covered with spines. Oblique and horizontal branches of slow and fast Pt neurons extend in layer V and some of them invade the lower part of layer III. It is suggested that this zone corresponds to a true fourth layer in the motor area. In both types of cells oblique and lateral branches bear numerous spines. Within the basal dendritic territory of Pt cells, one has to distinguish two dendritic systems: a short and a long one. The former spreads downward obliquely and appears to remain within layer V. The latter is made up of long descending vertical (antiapical) and oblique dendrites (tap root). While both types of cells may have long antiapical dendrites that run down radially to the lower part of layer VI, tap root dendrites which expand laterally below the cell body for considerable distances are a distinctive feature of fast Pt neurons. Though basal dendrites of all Pt cells bear spines, their number, distribution and shape are very variable in fast Pt cells.

Animals↗

PubMed1991

Identification of a common cyanobacterial symbiont associated with Azolla spp. through molecular and morphological characterization of free-living and symbiotic cyanobacteria.

Symbiotically associated cyanobacteria from Azolla mexicana and Azolla pinnata were isolated and cultured in a free-living state. Morphological analyses revealed differences between the free-living isolates and their symbiotic counterparts, as did restriction fragment length polymorphism (RFLP) analyses with both single-copy glnA and rbcS gene probes and a multicopy psbA gene probe. RFLP analyses with Anabaena sp. strain PCC 7120 nifD excision element probes, including an xisA gene probe, detected homologous sequences in DNA extracted from the free-living isolates. Sequences homologous to these probes were not detected in DNA from the symbiotically associated cyanobacteria. These analyses indicated that the isolates were not identical to the major cyanobacterial symbiont species residing in leaf cavities of Azolla spp. Nevertheless, striking similarities between several free-living isolates were observed. In every instance, the isolate from A. pinnata displayed banding patterns virtually identical to those of free-living cultures previously isolated from Azolla caroliniana and Azolla filiculoides. These results suggest the ubiquitous presence of a culturable minor cyanobacterial symbiont in at least three species of Azolla.

Blotting, Southern↗

PubMed1992

Morphological characterization of hypersensitive human radicular dentin and the effect of a light-curing resin liner on tubular occlusion.

A dentin biopsy technique was employed to compare the morphological features of hypersensitive and non-sensitive human radicular dentin. Specimens sampled from different areas in the same root surface displaying hypersensitivity or non-sensitivity were prepared for examination in the scanning electron microscope (SEM). Before analysis some specimens were exposed to surface demineralization and digestion of collagen to allow observation of subsurface portions of the dentinal tubules. In another set of observations the potential of a light-curing resin liner to penetrate root dentin in vitro and to maintain tubular occlusion over time following treatment of hypersensitive radicular dentin were examined. Orifices of many dentinal tubules were open in hypersensitive regions while non-sensitive areas generally displayed tubules occluded with mineralized material. SEM-images of HCl-collagenase treated specimens demonstrated the frequent presence of membrane-like structures in tubules of hypersensitive dentin. In non-sensitive dentin these structures were sparse. Topical application of a light-curing resin liner to wedge shaped defects prepared in radicular dentin of extracted human teeth resulted in a surface coating with a resin thickness of 20-50 microns. Resin penetrated dentinal tubules to a depth of more than 5 microns. Dentin biopsies examined 6 months after treatment with the liner showed presence of resin-like material in a majority of the tubules in dentin where hypersensitivity was no longer perceived. In none of the specimens did the liner remain as a surface coating. In areas of recurrent hypersensitivity more than half of the tubules presented with open orifices.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Etching, Dental↗

PubMed1991

Morphological characterization of rat entorhinal neurons in vivo: soma-dendritic structure and axonal domains.

We used in vivo intracellular labeling with horseradish peroxidase in order to study the soma-dendritic morphology and axonal projections of rat entorhinal neurons. The cells responded to hippocampal stimulation with inhibitory postsynaptic potentials, and thus likely received direct or indirect hippocampal input. All cells (n = 24) showed extensive dendritic domains that extended in some cases for more than 1 mm. The dendrites of layer II neurons were largely restricted to layers I and II or layers I-III, while the dendrites of deeper cells could extend through all cortical layers. Computed 3D rotations showed that the basilar dendrites of deep pyramids extended roughly parallel to the cortical layering, and that they were mostly confined to the layer containing the soma and layers immediately adjacent. Total dendritic lengths averaged 9.8 mm +/- 3.8 (SD), and ranged from 5 mm to more than 18 mm. Axonal processes could be visualized in 21 cells. Most of these showed axonal branching within the entorhinal cortex, sometimes extensive. Efferent axonal domains were reconstructed in detail in 3 layer II stellate cells. All 3 projected axons across the subicular complex to the dentate gyrus. One of these cells showed an extensive net-like axonal domain that also projected to several other structures, including the hippocampus proper, subicular complex, and the amygdalo-piriform transition area. The axons of layer III and IV cells projected to the angular bundle, where they continued in a rostral direction. In contrast to the layer II, III and IV cells, no efferent axonal branches leaving the entorhinal cortex could be visualized in 5 layer V neurons. The data indicate that entorhinal neurons can integrate input from a considerable volume of entorhinal cortex by virtue of their extensive dendritic domains, and provide a further basis for specifying the layers in which cells receive synaptic input. The extensive axonal branching pattern seen in most of the cells would support divergent propagation of their activity.

Animals↗

PubMed1992

Morphologic characterization and quantitative assessment of mitral regurgitation with ruptured chordae tendineae by transesophageal echocardiography.

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of morphologic characteristics and in the quantitative assessment of the severity of mitral regurgitation with ruptured chordae tendineae, 40 patients with ruptured chordae tendineae (group 1) and 20 patients with moderate or severe mitral regurgitation due to other causes (group 2) were studied. All echocardiograms were recorded before cardiac surgery. Cardiac catheterization was performed in 55 patients (92%). TEE showed greater sensitivity and negative predictive value than TTE (100 vs 65%, and 100 vs 56%, respectively; p < 0.005) in the diagnosis of ruptured chordae tendineae. Visualization of the ruptured chordae (termed snake-tongue sign) was highly sensitive and specific (93 and 95%, respectively) for establishing the diagnosis of ruptured chordae tendineae. The severity of mitral regurgitation in group 1 patients evaluated by TTE color flow mapping was underestimated by 2 grades in 1 patient and by 1 grade in 6 patients, and overestimated by 1 grade in 1 patient, compared with left ventriculography. In contrast, by TEE color flow mapping it was underestimated by 1 grade in 1 and overestimated by 1 grade in 1 patient. TEE color flow mapping showed better correlation with angiography than did TTE color flow mapping (r = 0.82 vs r = 0.49).

Adult↗

PubMed1992

Postnatal development of tyrosine hydroxylase immunoreactive amacrine cells in the rabbit retina: I. Morphological characterization.

The present and accompanying (Casini, G., and N.C. Brecha, J. Comp. Neurol. 326:302-313, 1992) papers investigate the postnatal development of tyrosine hydroxylase (TH)-immunoreactive (IR) amacrine cells in the rabbit retina. This study is focused on a detailed analysis of the patterns of cellular growth and differentiation of TH-IR amacrine cells, which serve as a model to gain insights into the mechanisms underlying developmental changes associated with the maturation of amacrine cells. Faintly staining TH-IR neurons are present in the proximal inner nuclear layer of newborn retinas. They are characterized by a large nucleus and usually a single primary process lacking varicosities. At postnatal day (PND) 6, TH-IR processes display more complex morphological characteristics, including a few varicosities, and second- and third-order ramifications. Growth cones are often seen. At PNDs 10 and 12 (eye opening), TH-IR cells have general morphological characteristics similar to adult TH-IR amacrines. They display 2-5 primary processes, which start forming a complex network of fibers in lamina 1 of the inner plexiform layer (IPL). TH-IR processes are also present in lamina 3 and rarely in lamina 5 of the IPL. Many fibers ending in growth cones are observed. In addition, very rare, thin TH-IR fibers are present in the outer plexiform layer. At PND 19, TH-IR fibers form a complex, dense network in lamina 1 of the IPL, and loose networks in laminae 3 and 5. Growth cones are not observed at this age. At PND 26, a few "ring-like" structures formed by TH-IR fibers in lamina 1 of the IPL are observed for the first time. In adult retinas, the "ring-like" structures are more numerous than at PND 26. A second, rare type of TH-IR cell ("type B") is encountered in all retinal regions beginning at PND 10. These cells are characterized by weak immunostaining and a small soma size. The present findings show that a significant differentiation of TH-IR neurons occurs during the first 10-12 PNDs. Eye opening is an important period for the maturation of TH-IR amacrines and, more generally, for the maturation of the IPL.

Animals↗

PubMed1979

Further morphological characterization and structural proteins of infectious bursal disease virus.

An outer layer surrounding the capsid of infectious bursal disease virus was evident from electron micrographs of intact virus particles having diameters of 62 to 63 nm. The capsid was found to be composed of large morphological units or capsomeres, measuring about 12 nm in diameter. The architecture of the capsid appears to be that of T = 3 symmetry, with a probable 32 morphological units by rotational enhancement of image detail. Structural proteins of infectious bursal disease virus consist of seven species, two major and five minor polypeptides. These are P1 to P7, with molecular weights of 133 x 10(3), 124 x 10(3), 98 x 10(3), 51 x 10(3), 33 x 10(3), 26 x 10(3), and 23 x 10(3), respectively.

Capsid↗

PubMed1979

Morphologic characterization of proliferative cells and virus particles in turkeys with lymphoproliferative disease.

The tumors found in turkeys having lymphoproliferative disease (LPD) are histologically characterized by a pleomorphic population of cells of the lymphoid series. Electron microscopy has shown that, despite marked differences in shape and size, the proliferating cells share basic ultrastructural features, indicating their lymphoid origin. Virus particles morphologically and morphogenetically characteristic of type C oncorna-viruses of Retraviridae were found in different organs and plasma samples of diseased or infected turkeys with LPD. This LPD type C virus resembled members of the reticuloendotheliosis virus group but not members of the avian sarcoma virus group.

Animals↗

PubMed1991

Morphological characterization of hemangiomatous tumors derived from a novel murine vascular endothelial cell line (F-2).

Hemangiomatous tumors were induced in Balb/c nude mice by inoculating F-2 cells (5 x 10(6)) from a novel tumorigenic murine endothelial cell line which had been established and maintained in our laboratories. These tumors were morphologically investigated in the course of development. Subcutaneous hemorrhage was observed at the inoculation site within 12 hours after the injection of F-2 cells, followed by development of skin tumors of various sizes at the same sites. They were dome-shaped, glossy surfaced, black, soft tumors. Mice finally died of massive blood loss due to internal and/or external hemorrhage (on day 10-77). Light microscopically, F-2 cells formed aggregates immediately after inoculation and then branched into a network of channels and cysts containing erythrocytes. Thereafter, spongiform structures composed of various sizes of cysts appeared with subsequent formation of a single large blood-filled cyst lined by one or two layers of thin cells. Under an electron microscope, F-2 cells, possessing large amounts of cytoplasm, formed narrow spaces which were occasionally incomplete with ambiguous basal lamina at the early stages. However, later, in large cysts, they became attenuated, tightly connected, and produced complete lumen surrounded by a basal lamina. Immunohistological demonstration of H-2 K, D antigen showed that tumors induced by F-2 cells mainly consisted of the inoculated F-2 cells. These results indicate that F-2 presents a good experimental system for investigation of vascular endothelial cell tumorigenesis and differentiation.

Animals↗

PubMed1992

Avian model for 13-cis-retinoic acid embryopathy: morphological characterization of ventricular septal defects.

In developing an avian model for 13-cis-retinoic acid (13cisRA) embryopathy, we found 13cisRA induced cardiovascular defects, especially Type I ventricular septal defects (VSDs) (Hart et al.: Teratology 41:463-472, '90). As the first step of investigating possible mechanisms, we have examined the light microscopic morphology of RA-induced cardiovascular defects in chick embryos. Fertilized eggs were injected via yolk sac with 150 micrograms 13cisRA in dimethylsulfoxide (DMSO), DMSO or mock injection on embryonic day 5 (E5). On E6, E7, or E8, surviving embryos were sacrificed and fixed in 10% formalin. Thoracic blocks were exised, embedded in paraffin and serially sectioned through the heart, base to apex. Slides were stained, screened for tissue orientation, then coded and evaluated without knowledge of treatment group. Examination of serial sections permitted qualitative evaluation of conotruncal ridge volume, mesenchymal organization, necrosis and extent of fusion. Extent of fusion was the only parameter influenced by 13cisRA treatment. On E6, ridge fusion was incomplete in all groups at comparable levels. On E7, ridge fusion in 13cisRA-treated embryos had not progressed as far proximally as in controls. By E8, there was a significant difference in the extent of fusion between 13cisRA-treated and non-RA-treated groups. We conclude 13cisRA-induced VSDs resulted from defective conotruncal ridge fusion and that the fusion defects did not result from decreased tissue volume, altered mesenchymal organization or increased necrosis.

Animals↗

PubMed1977

Spermatogenic cells of the prepuberal mouse. Isolation and morphological characterization.

A procedure is described which permits the isolation from the prepuberal mouse testis of highly purified populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene primary spermatocytes, leptotene and zygotene primary spermatocytes, pachytene primary spermatocytes and Sertoli cells. The successful isolation of these prepuberal cell types was accomplished by: (a) defining distinctive morphological characteristics of the cells, (b) determining the temporal appearance of spermatogenic cells during prepuberal development, (c) isolating purified seminiferous cords, after dissociation of the testis with collagenase, (d) separating the trypsin-dispersed seminiferous cells by sedimentation velocity at unit gravity, and (e) assessing the identity and purity of the isolated cell types by microscopy. The seminiferous epithelium from day 6 animals contains only primitive type A spermatogonia and Sertoli cells. Type A and type B spermatogonia are present by day 8. At day 10, meiotic prophase is initiated, with the germ cells reaching the early and late pachytene stages by 14 and 18, respectively. Secondary spermatocytes and haploid spermatids appear throughout this developmental period. The purity and optimum day for the recovery of specific cell types are as follows: day 6, Sertoli cells (purity>99 percent) and primitive type A spermatogonia (90 percent); day 8, type A spermatogonia (91 percent) and type B spermatogonia (76 percent); day 18, preleptotene spermatocytes (93 percent), leptotene/zygotene spermatocytes (52 percent), and pachytene spermatocytes (89 percent), leptotene/zygotene spermatocytes (52 percent), and pachytene spermatocytes (89 percent).

Age Factors↗

PubMed1991

Morphologic characterization of conjunctiva-associated lymphoid tissue in chickens.

Conjunctiva-associated lymphoid tissue (CALT) in the eyelids of chickens was studied by gross, histologic, and electron microscopic techniques. Structural features were characterized at 1 day of age and at posthatching week (PHW) 1, 2, 3, 4, 6, 8, 12, and 16. Beginning at PHW 1, prominent lymphoid nodules containing a heterogenous population of lymphocytes, lymphoblasts, and macrophages were first observed within conjunctival folds and fissures of the lower eyelid. Nodules contained germinal centers by PHW 2 and plasma cells by PHW 4. The epithelium associated with these nodules was flat, had short, irregular microvilli, contained intraepithelial lymphocytes, and lacked goblet cells. High endothelial venules were located at the base of lymphoid nodules and contained lymphocytes within and below the cuboidal endothelium. In the upper eyelid, CALT was morphologically similar to lymphoid tissue in the lower eyelid, but nodules were smaller and more random, lacked association with epithelial folds and fissures, and were clustered around the opening of the nasolacrimal duct. By PHW 12, CALT was characterized by basal germinal centers outlined by collagenous stroma, suprafollicular plasma cells, columnar epithelium with goblet cells, and fewer intraepithelial lymphocytes. On the basis of these features, CALT in chickens has morphologic characteristics similar to other components of the mucosal immune system and, therefore, may have a role in mucosal immunity.

Animals↗

PubMed1991

Morphological characterization of human juxtaglomerular apparatus.

The recent demonstration of the endothelial fenestration at the juxtaglomerular part of the afferent arteriole facing mesangial and granular cells and finger-like protrusions of urinary space into the region of the lacis in experimental animals like the rat, the mouse, and Tupaia belangeri led us to propose the hypothesis of a "short loop" feedback mechanism. To establish whether a further species possesses these morphological features, the JGA region was examined in the human kidney. Tissue was obtained by needle biopsy from patients and conventional electron-microscopical procedures including serial sections were utilized to reevaluate the morphology of JGA. Both the endothelial fenestration in the wall of the afferent arteriole and protrusions with filtration slits of urinary space into the lacis, were observed with remarkable heterogeneity. The occurrence of these features of JGA in such diverse mammalian species as rat, mouse, Tupaia, and man suggests that these structures may be involved in regulatory process and the proposed "short loop" feedback mechanism may be a general phenomenon.

Animals↗