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  • 1
    Electronic Resource
    Electronic Resource
    Postnatal maturation of the rabbit cortical collecting duct (1988)
    Springer
    Pediatric nephrology 2 (1988), S. 135-145 
    Details
    ISSN: 1432-198X
    Keywords: Cortical collecting duct ; Potassium ; Mitosis ; Helium glow photometry ; Quartz fiber balance ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mature, fully differentiated cortical collecting duct plays a major role in the final renal regulation of Na+, K+ and H+ transport. To characterize the growth of this segment, we measured the outer diameter and the dry weight of cortical collecting ducts isolated from newborn, 1-month-old, and adult rabbits. During the 1st month of life no significant changes were observed; however, there was a 60% increase in both parameters after the 4th week of life. Growth-related accretion of K+ was demonstrated by showing tubular K+ content to increase by 60% with maturation. Concomitant with the increase in tubular size, total cell number per millimeter of tubular length rose by 30%. Approximately 50% of the observed increment in tubular size could be accounted for by cell hyperplasia, with the remaining increase resulting from cell hypertrophy. Hypertrophy of principal cells was confirmed by scanning electron microscopy, which demonstrated a doubling of the circumferential width without any change in longitudinal length. Hyperplasia was confirmed, using a fluorescent chromatin stain, by our finding of a mitotic frequency of 3/1000 cells in the neonatal mid-cortical collecting duct; the observed number of mitoses was 10-fold higher at the most cortical end (ampulla). The number of intercalated cells per millimeter of tubule length, identified by bright green fluorescence after cortical collecting ducts were stained with 6-carboxyfluorescein diacetate, was found to double during maturation, the increase being significant only after the 4th postnatal week. We conclude that maturation of the mid-cortical collecting duct results from both cellular hyperplasia and hypertrophy. It is unlikely that this segment plays a major role in regulating Na+, K+, and H+ transport in the neonatal kidney.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00870394
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  • 2
    Electronic Resource
    Electronic Resource
    Human cystic kidney diseases: epithelial hyperplasia in the pathogenesis of cysts and tumors (1987)
    Springer
    Pediatric nephrology 1 (1987), S. 393-396 
    Details
    ISSN: 1432-198X
    Keywords: Polycystic kidney disease ; Renal carcinoma ; Tuberous sclerosis ; von Hippel-Lindau disease ; Acquired renal cystic disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several examples of human renal cystic disease are associated with tubular epithelial hyperplasia. Micropapillary hyperplasia occurs in autosomal dominant polycystic kidney disease, in localized cystic disease, and in acquired cystic disease; neoplastic or severely dysplastic epithelial hyperplasia occurs in von Hippel-Lindau disease; a histopathologically distinctive epithelial hyperplasia occurs in tuberous sclerosis. In all of these conditions the epithelial hyperplasia appears to be responsible for cyst formation by causing tubular or ductal luminal obstruction, and in all of these conditions, save localized cystic disease (a rare condition with very few reported cases), epithelial hyperplasia imposes an increased risk of malignancy. The risk seems to be highest in patients under treatment with long-term hemodialysis for end-stage kidney disease. Some of these diseases may share common features, but it appears likely that the histopathological differences reflect different features converging on a common result.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00849242
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  • 3
    Electronic Resource
    Electronic Resource
    MDCK cysts: An in vitro model of epithelial cyst formation and growth (1986)
    Springer
    Methods in cell science 10 (1986), S. 245-248 
    Details
    ISSN: 1573-0603
    Keywords: MDCK cell ; renal cell culture ; epithelial cysts ; collagen gel ; clonal growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary MDCK cells dissociated from monolayer culture were either dispersed within medium-hydrated collagen gel or seeded atop a collagen substrate which was immediately overlaid with collagen gel. Individual cells exhibited clonal growth in three dimensions to form spherical cysts in which a simple epithelium surrounded a fluid-filled lumen. The cells of MDCK cysts were polarized with apical surface bordering the lumen. MDCK cysts increased in diameter with continued culture. Maximum cyst size was dependent on seeding density and was influenced by medium composition. MDCK cysts could be isolated from the collagen substrate by digestion with collagenase. Also, collagen gel could be dissected from the cyst wall to give unrestricted access to regions of the basolateral cell surface. This novel method of renal cell culture provides a study system to model the influence of the extracellular matrix on kidney epithelial cell structure and function. It also offers an in vitro model of general application to the study of epithelial cyst formation and growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01404485
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  • 4
    Electronic Resource
    Electronic Resource
    The structure of the hypothalamic inferior lobes of the blacktip reef shark: Scanning and transmission electron microscopic observations (1976)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 59-78 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The inferior lobes of the shark hypothalamus were examined with light, transmission and scanning electron microscopy. The cells bordering the floor of the lateral recess appear to be typical liquor-contacting neurons. With scanning electron microscopy (SEM) the apical ends of these cells are seen to bulge into the ventricular lumen. In contrast, the roof is lined by a more typical ependymal cell characterized by numerous cilia and microvilli. In addition, SEM reveals several kinds of supraependymal cells with processes that appear to penetrate the ventricular lining. A periventricular nucleus underlies the ependymal cells. Neurons of the periventricular nucleus contain numerous lipofuchsin granules. The rest of the inferior lobe consists of many neuronal fibers. The morphology of the hypothalamic inferior lobe is discussed in relation to its possible role in feeding and aggressive behavior in both elasmobranchs and teleosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051500104
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of chronic deafferentation on adrenergic ganglion cells and small intensely fluorescent cells (1978)
    Springer
    Journal of neurocytology 7 (1978), S. 25-37 
    Details
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the reaction of adrenergic ganglion cells and small intensely fluorescent (SIF) cells to chronic deafferentation, catecholamine fluorescence of the major pelvic ganglion (MPG) of the rat has been studied following section of the hypogastric nerve, pelvic nerve and sympathetic trunk. Only minor changes occurred following section of the hypogastric nerve; the fluorescence surrounding a few adrenergic ganglion cells became brighter. In contrast, pelvic neurectomy resulted in the appearance of numerous varicose fibres and an increase in the fluorescent intensity of fibres enclosing many ganglion cells. Varicose fibres seem to originate from adrenergic ganglion cells and SIF cells. In many instances, nests of SIF cells gave rise to radially oriented fibres. Removal of the sympathetic trunk appeared to have no effect on the MPG. It is suggested that the appearance of varicose fibres from SIF cells following deafferentation may be due to collateral sprouting of these cells or to the increased fluorescence of pre-existing processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213458
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  • 6
    Electronic Resource
    Electronic Resource
    The major ganglion in the pelvic plexus of the male rat (1975)
    Springer
    Cell & tissue research 159 (1975), S. 49-62 
    Details
    ISSN: 1432-0878
    Keywords: Autonomic ganglia ; Pelvic plexus ; SIF cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To further evaluate the role of autonomic ganglia in the regulation of pelvic visceral activity, the neural elements in the major pelvic ganglion of the male rat have been studied with histochemical and electron microscopic techniques. The principal findings are that the ganglion is composed of cholinergic and adrenergic ganglion cells as well as small intensely fluorescent (SIF) cells. Polarity in the ganglion is indicated by clustering of small ganglion cells which stain intensely for acetylcholinesterase (AChE) along the pelvic nerve while larger cells, with weak to moderate AChE activity, collect near small branches of the hypogastric nerve. Some cholinergic ganglion cells are enclosed by a plexus of adrenergic terminals. SIF cells appear to be in contact with both cholinergic and adrenergic cells, although many of the fluorescent beads around adrenergic neurons may be short dendrites of ganglion cells, rather than processes of SIF cells. Two types of SIF cells may be distinguished on the basis of size and morphology of their granulated vesicles. Afferent synapses of the cholinergic type were common on SIF cells of the large granule and small granule type. Portions of SIF cells with large granules occur within the capsule of ganglion cells. Contacts seen here were interpreted as efferent synapses from SIF cells to the dendrites of ganglion cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231994
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  • 7
    Electronic Resource
    Electronic Resource
    Zonulae occludentes of the rat nephron under conditions of experimental expansion of blood and/or fluid volume (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 186 (1976), S. 139-150 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The zonula occludens (Z.O.) has been implicated as a major pathway for passive fluid movement from lateral intercellular spaces to lumen in response to an expansion of blood or fluid volume. The present study examines the Z.O. of adult rat nephrons in control and Ringer-Locke or whole blood infused animals to determine whether varying the conditions of passive fluid movement would influence the structure of the Z.O. Rats were infused over 20 minutes with Ringer-Locke (7% body weight) or whole blood (2.3% body weight). In the controls, 92%-94% of all Z.O. observed in proximal tubules and 100% of Z.O. from distal tubules and collecting ducts had fused outer leaflets. The approximate linear extent of the Z.O. was 140 Å for proximal tubules, 2,500 ÅR for distal tubules and 3,000 ÅR for collecting ducts. There was no significant difference in any of these values following the infusion with either Ringer-Locke or whole blood. We conclude that expansion of blood or fluid volume causes no detectable alteration in the fine structure of Z.O. under the conditions used in the present study.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091860202
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  • 8
    Electronic Resource
    Electronic Resource
    Efferent arterioles in the cortex of the rat kidney (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 187 (1977), S. 135-145 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Although a number of morphological studies have investigated the vascular system of the rat kidney, minimal data are available on the detailed anatomy of the efferent arterioles located throughout the cortex of the kidney. In the present study, the renal vascular system was filled with Microfil and the various efferent arteriole patterns were examined extensively. The efferent vessels of the entire cortex appear to form three major patterns which in turn divided the cortex into three separate regions: the outer, middle and inner cortex. The efferent arterioles of the outer cortex leave the glomerulus and run perpendicular to the kidney capsule. However, as the efferent arterioles ascend, they may show three variations in the way they branch: (1a) the efferent arteriole does not branch until directly beneath the capsule, (1b) the efferent vessel begins to divide into its major branches 100-200 μm below the surface of the kidney and (1c) the efferent vessel has only a short course before giving off many side branches. In the middle cortical area, the branches of the efferent arteriole run lateral to the glomerulus. However, the efferent arterioles of the inner cortex have a few branches which run lateral to the glomerulus while most of them descend into the medulla as vasa rectae. The unique morphological features of the efferent arterioles of the outer cortex are of particular interest in light of the functional data which suggests that the reabsorption of fluid by peritubular capillaries may indeed regulate the rate of net tubular sodium reabsorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091870202
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  • 9
    Electronic Resource
    Electronic Resource
    Maturation of the proximal tubule in the puppy kidney:A comparison to the adult (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 195 (1979), S. 273-299 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Two- to four- day- old beagle puppy kidneys were prepared fortransmission and scanning electron microscopy and compared to similarly prepared adult tissues. proximal tubules of puppy kidneys which contained nephrons in various stages of differentiation were examined andmaturational changes were described. Lateral surface contours of proximal tubular cells were initially smooth and relatively unfolded, but progressively acquired complex processes that may be recognized as lateral ridges and lateral-basal processes. Basal projections began as short, stubby processes and gradually took on either a narrow, plate-like or finger-like appearance. Mitochondria, lysosomes and apical vacuoles increased in number as the tubules matured. Mitochondria lacked orientation in outer cortical tubules, but exhibited some vertical arrangement within basal processes in inner cortical tubules. Despite features indicating advanced maturation of tubules in the inner cortex, puppy kidneys lacked the lipid droplets characteristic of the adult. Thus, differentiation of this portion of the developing nephron into S, S2 and S, segments was notpossible at day 4.Morphometric analyses of the lateral and basal membrane surface concentrationof proximal convoluted tubules from the puppy revealed all cells to have significantly smaller membrane area than that of the adult. However, the inner cortical cells of the puppy had a greater surface concentration than those of the outer cortex. The reduced transport capacity of the puppy proximal tubule may be related to the lack of segmentation and/or reduced lateral-basal surface area.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091950204
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  • 10
    Electronic Resource
    Electronic Resource
    Maturation of the glomerular visceral epithelium and capillary endothelium in the puppy kidney (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 193 (1979), S. 1-21 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The present study describes the development and maturation of the glomerular visceral epithelium and capillary endothelium in an attempt to clarify kidney function in the neonate. The puppy kidney undergoes nephrogenesis for at least two weeks after birth, and thus possesses nephrons of different ages and levels of maturation. Since nephron development varies considerably from inner to outer cortex, renal corpuscles were examined within three arbitrary zones (outer, middle and inner cortex). The visceral epithelium of the smallest glomeruli, i.e., those of the outer cortex, is composed of cuboidal cells which are densely clustered and rests directly upon the limited number of small capillaries. More deeply within the outer cortex, broad, flat epithelial processes extend around the capillary, but lack any visible pedicels. Mid cortical glomerular capillaries undergo an increase in diameter and length, and at the same time the podocytes flatten and separate from one another. Pedicels begin to appear in this zone as thickened, disorganized processes. Juxtamedullary glomeruli are the largest, due primarily to their extensive capillary branching (looping). Podocytes are nearly adult-like in appearance, with many long primary processes and pedicels.The endothelial morphology of glomerular capillaries varies from one loop to another, as well as within a single loop. The immature endothelium of outer glomeruli is initially characterized by extensive expanses lacking pores, multiple cellular layers and small, scattered pinholes. Greater capillary maturity is apparent in the mid cortex, due to an increase in pore number and diameter as well as greater attenuation of endothelial cells. However, evidence of remodeling and a lack of pores still exists in some capillaries. The glomerular capillaries of the inner cortex appear the most mature, but possess regions that are still immature when compared to the adult.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091930102
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