Modulation of the population density of identifiable epidermal Langerhans cells associated with enhancement or suppression of cutaneous immune reactivity

The epidermis on the backs or ears of DBA/2 mice treated for 7 days with a 20% concentration of monobenzyl ether of hydroquinone (MBEH) had a significantly greater population density of ATPase- and Ia-positive cells compared with control mice treated with diluent. There was no decrease or increase in ATPase- or Ia-positive cells at sites distal from the treated tissue. This increase in population density of Langerhans cells was associated with a significant increase in functional afferent immune reactivity measured by allergic contact hypersensitivity. We also found evidence for enhanced efferent immune reactivity. Animals treated on the ears for 7 days with MBEH were sensitized to DNFB on untreated back. MBEH treated ears with more Ia-positive Langerhans cells demonstrated a threefold greater increase in swelling after the DNFB challenge than the control mice. Results of other studies suggest that the afferent and efferent enhanced immune reactivity produced by MBEH are local effects. We postulated that MBEH produced its effects by activating the oxidation of arachidonic acid (AA) to prostaglandins. To test this, we applied AA to mouse skin. AA has a biphasic effect on epidermal Langerhans cells: in low doses it increases their number; in high amounts it decreases the number of identifiable cells with either the Ia or the ATPase technique. An increased population density of identifiable epidermal Langerhans cells induced with AA was correlated with an increase in afferent and efferent immune reactivity. In contrast, reduction of Langerhans cells with larger amounts of AA suppress the afferent and efferent limb of the immune response. DNFB applied to skin with decreased Langerhans cell density from AA induced a state that mimics immune tolerance. The findings are significant because we report the only method to either increase or decrease the population density of Langerhans cells: and to modulate up or down the afferent or efferent limbs of the cutaneous immune response. Our results also suggest that the Langerhans cell may be involved in the efferent limb of the immune efferent response. These effects may be modulated in part by products of AA metabolism.     

EphB4 receptor tyrosine kinase transgenic mice develop glomerulopathies reminiscent of aglomerular vascular shunts

We have established transgenic mice over-expressing the EphB4 receptor tyrosine kinase in the kidney. The EphB4 protein was localised to the developing tubular system of both control and transgenic newborn mice. In transgenic adults, transgene expression persisted in the proximal tubules and the Bowman's capsules, structures, which were not stained in control kidneys. The glomeruli of control animals consisted of regular, round vascular baskets with clearly discernable afferent and efferent arterioles. In contrast, approximately 40% of the transgenic glomeruli had an irregular shrivelled appearance and many exhibited fused, horse shoe-like afferent and efferent arterioles bypassing the glomerulus. These abnormal glomerular structures are very reminiscent of aglomerular vascular shunts, a human degenerative glomerulopathy of unknown aetiology.     

An ultrastructural study of the development of afferent and efferent synapses on outer hair cells of the guinea pig organ of Corti

The guinea pig organ of Corti was studied using transmission electron microscopy, the second turn of the cochlea being examined at various ages between 20 days before birth and 30 days postnatal. Outer hair cells were examined at each of these ages. At all ages studied, the efferent (presynaptic) terminals are large and are packed with synaptic vesicles, whereas the afferent (postsynaptic) terminals are generally smaller, with a relatively small number of vesicles. During development, the subsynaptic cistern changes from a fragmented, diffuse profile extending over 50-70% of the length of the efferent contact zones, to a continuous, compact structure spanning neighbouring synapses. Synaptic vesicles in the efferent terminals are predominantly rounded in early development, flattened vesicles appearing postnatally. The synaptic bodies at afferent synapses do not change noticeably during development. Quantitative analysis revealed that the area of efferent terminals and the length of their active zone increase with increasing age, the same parameters decreasing in afferent terminals. Synaptic vesicles in the efferent terminals decrease in diameter, but remain constant in afferent terminals, with increasing age. The number of hair cell membrane invaginations decreases as development proceeds.     

Aglomerular pathways in intrarenal microvasculature of aged rats

By means of silicone rubber injections, we confirmed the existence of several types of aglomerular arterial pathways within kidneys of aged rats. In superficial cortex some interlobular arteries divide to form aglomerular branches (Ludwig's arterioles) towards cortex corticis. In juxtamedullary cortex these pathways are relatively more numerous, they comprise: (a) Vasa Recta Vera, (b) glomeruli in which afferent and efferent arterioles form a continuous vessel and (c) glomeruli with two efferent vessels, one by-passing glomerular tuft. In addition, results obtained in the rat by the microsphere technique are in agreement with our morphological observations.     

Formation of new synaptic contacts by Purkinje axon collaterals in the granular layer of deafferented cerebellar cortex of adult rat

In addition to (i) mossy terminals, (ii) Golgi axons, (iii) granule cell dendrites and (iv), occasionally, Golgi cell dendrites, a third axonal profile identified by morphological criteria as the collateral of Purkinje axons, has been found in 2% of all cerebellar glomeruli. These infrequent components of a few glomeruli, however, were never seen in normal cerebellar cortex to establish specialized synaptic contact with glomerular dendrites. Two to four weeks after surgical isolation of the cerebellar cortex, i.e. following the destruction of both efferent and afferent fibres, the number of glomeruli containing (hypertrophic) axonal branches of Purkinje cells has increased to 13% of all surveyed glomeruli. In addition, the Purkinje axon terminals in the mossy fibre-deprived glomeruli were observed to establish numerous Gray II-type synaptic contacts with surrounding granule cell dendrites. It is suggested that the development of heterologous synapses between hypertrophic, or even intact, Purkinje axon collaterals on the one hand and the mossy fibre-vacated granule cell dendrites on the other, is a compensatory, reactive process to the synaptic "desaturation" of granule neurons, which demonstrate a dormant potential of Purkinje cells to form new synaptic contacts in the adult cerebellum.     

大鼠肾小球微循环活体观察实验研究

结扎大鼠一侧输尿管,复制肾盂积水模型。在冷光源－光导纤维－导光棒的透射照明下,通过显微电视系统,成功地观察到完整肾脏皮质表层肾小球及其周围血管微血流动态的清晰图像。正常肾小球呈树状分布,密集、大小均匀。高倍镜下可清楚辨认入球及出球小动脉,其血细胞流态为直线状。并发现肾小球有交替开放现象。     

Effects of angiotensin II on regional afferent and efferent arteriole dimensions and the glomerular pole

The diversity of renal arteriole diameters in different cortical regions has important consequences for control of glomerular capillary pressure. We examined whether intrarenal angiotensin II (ANG II; 0.1, 1, or 5 ng. kg(-1). min(-1)) in anesthetized rabbits acts preferentially on pre- or postglomerular vessels using vascular casting. ANG II produced dose-related reductions in afferent and efferent diameters in the outer, mid, and inner cortex, without effecting arterial pressure. Afferent diameter decreased more than efferent in the outer and mid cortex (P < 0.05) but by a similar extent in juxtamedullary nephrons (P = 0.58). Calculated efferent resistance increased more than afferent, especially in the outer cortex (127 vs. 24 units; 5 ng. kg(-1). min(-1) ANG II). ANG II produced significant dose-related increases in the distance between the arterioles at the entrance to the glomerular pole in all regions. Thus afferent diameter decreased more in response to ANG II, but efferent resistance rose more due to smaller resting luminal dimensions. The results also indicate that glomerular pole dimensions change in response to ANG II.     

An electron microscopic study on the innervation of the gill filaments of a lamprey,Lampetra japonica

This paper reports observations on the innervation of gill filaments of the lamprey, Lampetra japonica. Nerve fibers run on each side of the afferent filament artery (AFA nerve) and in the connective tissue compartment along the efferent filament artery (EFA nerve). The AFA nerve supplies vasomotor fibers to the afferent filament artery and arteriovenous anastomoses and special visceral motor fibers to branchial muscle fibers (musculus compressor branchialis circularis). Nerve endings of the vasomotor fibers contain large, cored vesicles (60–180 nm in diameter) with a variable number of small, clear vesicles (30–70 μm in diameter), whereas those of the visceral motor fibers have many small, clear vesicles with few large, cored vesicles. The EFA nerve supplies vasomotor fibers to the efferent filament artery. Their endings, containing mixtures of predominantly large, cored vesicles and small, clear vesicles make close synaptic contacts with reticular cells. The latter in turn are connected with each other or with smooth muscle cells in the wall of the efferent filament artery by nexuses. No nerves are found in the axial plate between the afferent and efferent filament arteries nor in the secondary lamellae of individual gill filaments. No afferent nerve supply to the gill filament has been found.     

Study of glomerular vasculature in teleosts with the resin-replica method

Glomerular vasculature was investigated in the carpCyprinus carpio, the scorpionfishSebastiscus marmoratus, and the marine catfishPlotosus lineatus with the resin-replica method. An afferent arteriole was connected with a glomerulus in every fish. It was slender in the carp, whereas the scorpionfish and marine catfish possessed thick afferent arterioles. The glomerular capillaries were sinusoidal. The divergences, convergences, and windings of these capillaries were not well developed in any of the fish. The glomerular capillaries converged into an efferent arteriole in the carp and scorpionfish. In the marine catfish, on the other hand, most of the glomeruli had two efferent arterioles.     

Cortical microvasculature of the feline kidney

Scanning electron microscopy of corrosion casts was used to study the ultrastructural morphology of the microcirculation in the feline kidney. The technique used enabled us to examine the renal microvasculature by obtaining stable and consistent replicas of the vasculature. Corrosion casts were evaluated at three different levels, namely subcapsular, midcortical and the corticomedullary junction. The interlobular arteries, given off by the arcuate arteries, coursed through the cortex in a radial fashion and afferent arterioles were given off at varying intervals. Large afferent arterioles formed the glomerular capillary lobules which consisted of very tortuous capillaries. Smaller-diameter efferent arterioles were formed at the vascular pole and ran in the opposite direction to the afferent arteriole. The peritubular plexuses were seen as interconnecting capillaries at both the subcapsular, midcortical and corticomedullary junction. Numerous efferent arterioles, derived from the corticomedullary glomeruli, were seen as large, radiating vessels running towards the renal papilla.     

Anatomy and topography of the lymphatic vessels and regional lymph nodes of the rectum in newborn infants and children to 3 years of age

In 30 corpses of newborns and children up to 3 years of age, by means of the intratissue and direct injection of the modified Gerota's mass, certain increase in number and size of the superficial inguinal lymph vessels belonging to the superior-medial group, as well as the pararectal and superior rectal lymph nodes has been noted. The diameter of both afferent and efferent lymphatic vessels in the nodes mentioned in children of 1-3 years of age is greater than in the newborns. The number of the afferent vessels running towards these nodes in most cases, regardless the age, prevail over the efferent ones, and the diameter of the latter is greater than in the afferent vessels. The pararectal lymph nodes in 80% of cases are the nodes of the first step for the lymph flowing from the rectum, in 15% - the nodes of the first and second steps, simultaneously, and in 5% - of the third and fourth steps. The superior pararectal lymph nodes in 80% of cases are the nodes of the third and fourth steps, and in 20% of cases - those of the first and second steps for the lymph flowing from the rectum.     

The distribution of renin in the different segments of the renal arterial tree

Summary The intrarenal distribution of renin in the mouse kidney was evaluated in a semiquantitative immunocytochemical study using an antiserum against pure mouse renin and the PAP technique. The bulk of renin positive cells was found in the media of the afferent arteriole. When examining the geometry of renin distribution about 35% of the afferent vessels were seen to be renin positive only over a distance of 20 m, about 60% over a distance of 30 m. In the remaining afferent arterioles, renin was also found upstream over distances up to 100 or even 200 m. These results are discussed with regard to the stimuli for renin secretion, especially the macula densa signal. — At the vascular pole of the glomerulus, virtually 100% of the afferent, and 20%–40% of the efferent arterioles were found to be renin positive at an antiserum dilution of 1:1,000. As some efferent vessels — especially those of the juxtamedullar region — show scattered activity occasionally over a distance of more than 100 m, it is suggested that the figure of 20%–40% should be taken as a minimal count for renin positive efferent arterioles. — To compare the renin content of superficial and juxtamedullary, afferent and efferent arterioles in normal salt and salt depleted mice, the fraction of positive renin reactions close to the vascular pole was determined at antiserum concentrations of 10^–3, 10^–4, 2×10^–4 and 10^–5. By this semiquantitative immunocytochemical method the afferent arterioles of superficial glomeruli could be shown to contain significantly higher renin concentrations than those of juxtamedullar glomeruli. This result was in agreement with biochemical renin estimations in mouse kidney slices taken from cortical and juxtamedullar sites. Sodium deprivation was followed by only a slight elevation of the fraction of positive superficial afferent arterioles (confirmed by the biochemical data). In contrast, sodium deprivation induced a highly significant increase of the number of positive superficial efferent vessels. This result is discussed with regard to (controversial) reports on a preferential efferent vasoconstrictor tone sustained by angiotensin II especially under the condition of sodium depletion. Juxtamedullar vasa afferentia and efferentia did not respond significantly to sodium restriction. —The Goormaghtigh cell field was found to be renin negative in superficial as well as in juxtamedullar glomeruli both in normal salt and salt deprived mice. Inspecting nearly 5,000 glomeruli, only 5 clearly renin positive mesangial cells were seen close to the glomerular stalk. In contrast, renin positive media cells could not seldom be seen in interlobular arteries and at the point of their branching into afferent arterioles.A first account of these results was given at the Rottach-Egern Satellite Symposium of the VIIth International Congress of Nephrology: The juxtaglomerular apparatus and the tubuloglomerular feedback mechanism — morphology, biochemistry and function, June 3 to 5, 1981These studies were supported by the Deutsche Forschungsgemeinschaft within the SFB 90 Cardiovasculäres System     

Glomerular bypass shunts and distribution of glomeruli in the kidney of the lesser spotted dogfish,Scyliorhinus caniculus

Summary Scanning electron microscopy of corroded resin casts of the renal vasculature of Scyliorhinus caniculus has revealed a novel vascular pathway arising from the afferent arteriole and bypassing the glomerulus. This glomerulus bypass shunt occurred in 36% of the glomerular casts examined. The shunt ran to join a peritubular network of capillaries and thereby offers the potential to vary the degree of glomerular perfusion and control the proportion of active glomeruli. In 29% of glomeruli two efferent arterioles drained the capillary knot. Glomeruli were located close to the dorsal margin of the posterior mass of the kidney, and towards the lateral edge of the anterior lobes of the kidney of female dogfish. In male dogfish, glomeruli were evenly distributed through the posterior mass of kidney, while in female dogfish 89% of glomeruli occurred in the posterior mass and 11% of glomeruli were located within the small anterior lobes.     

The brain of the horseshoe crab (Limulus polyphemus). III. Cellular and synaptic organization of the corpora pedunculata.

The large, hemispherical mass of the Limulus corpora pedunculata consists of two highly branched lobes, each connected to the protocerebrum by a narrow stalk. About 10(4) afferent fibers enter through the stalks and make diverse, profuse, and often reciprocal contacts with several million Kenyon (intrinsic) cells and one another. The Kenyon cell axonal arborizations converge on a few hundred efferent dendrites. The afferent fiber types can be classified into five types. Type A forms the club-shaped core of glomeruli and circumglomerular annuli, and contains small flat vesicles, suggesting an inhibitory function. Type B terminates with bushy endings in glomeruli and is presynaptic to both Kenyon cells and to Type A terminals. It has clear round vesicles and is the presumptive excitatory input. Type C terminates on other afferents, in glomeruli, and rarely on Kenyon cell bodies, contains angular (neurosecretory) granules and is postulated to impart circadian rhythm. Type D terminates on Kenyon cell somata and the initial neurite segment (but not in glomeruli), and contains dense-cored vesicles. Type E terminates in peduncles on other afferents and Kenyon cell telodendria. It contains dense vesicles. The C, D, and E afferents have reciprocal synaptic connections with Kenyon cell axon terminals. Glomeruli thus receive three different inputs of presumptive inhibitory (A), excitatory (B), and neuromodulatory nature (C). Kenyon cells, increasing in number up to about 1 x 10(8) in the adult, show minor variations in their dendritic pattern and have only one rare variant cell type. Interactions between them occur primarily at their axonal boutons as they crowd around efferent fibers. The latter have large receptive fields, some of their large somata are located within the confines of the corpora pedunculata, and they receive input almost only from Kenyon cells. Numerical and directional details of the circuitry in the corpora pedunculata have been extracted by a combination of light and electron microscopy, serial sectioning, silver staining, and stereology. The corpora pedunculata appear to process primarily the voluminous chemosensory input from the appendages, an assumption that is supported by the major connections of the organ.     

Vascularization and glomerular ultrastructure in the pig mesonephros

Summary Vascularization of the pig mesonephros was investigated in embryos 5–8 cm in length. Vascular injections with microfil were cleared and dissected; corrosion casts were studied under the scanning electron microscope (SEM). Perfusion-fixed tissue was used for SEM and transmission electron microscope (TEM) studies, including freeze-fracture specimens.The branches of one mesonephric artery carry up to 15 glomeruli. Several glomeruli occupy the same arterial branch, with very short afferent arterioles proper. The efferent vessels, frequently 2–5, leave the extensive vascular pole opposite the entering arteriole and split into peritubular capillaries radiating towards the superficial veins. These capillaries form vascular regions in the shape of flattened pyramids. Along its course, one nephron is supplied by vessels derived from 4–7 glomeruli. The nephrons have less vascular contact than in the definitive kidney.The ultrastructure of the single mesonephric vessels matches the metanephric counterparts. Epithelioid cells with renin granules are common in afferent arterioles, larger arteries, and efferent vessels. The lobulated glomeruli are up to 750 m long and flattened, showing the usual features of podocytes, mesangial cells, and an attenuated endothelium with fenestrations between 50 and 250 m. It partially retains its own basement membrane. There is no proximal mesangium.Supported by Deutsche Forschungsgemeinschaft.     

Lymphocyte traffic through granulomas: Differences in the recovery of indium-111-labeled lymphocytes in afferent and efferent lymph

Afferent lymphatics draining granulomas and efferent lymphatics from normal and stimulated lymph nodes were cannulated in sheep. There was a greatly increased output of cells in afferent lymph-draining chronic inflammatory sites or Freund's adjuvant-induced granulomas. Cells collected from these lymphatics were radiolabeled with ¹¹¹In and injected intravenously. The reappearance of these labeled cells in lymph at various sites was measured. Labeled afferent lymph cells migrated from blood through the granuloma back into afferent lymph in large numbers and with kinetics which were comparable to efferent lymphocytes recirculating through a lymph node. When labeled afferent lymph cells were injected the specific activity (cpm/10⁷ cells) in afferent lymph was five times higher than that in efferent lymph from a normal node. When efferent lymph cells were labeled the afferent lymph specific activity was one-half that in efferent lymph. It is suggested that the cells in afferent lymph migrate preferentially from blood through the granuloma and constitute a unique population of cells.     

Morphometric characteristics of neuromuscular spindles in hypertrophied skeletal muscle

Skeletal muscle hypertrophy in young male rats was found to be accompanied by adaptive changes in neuromuscular spindles. The changes consisted in connective capsule thickening, increased diameter of NMS and intrafusal muscle fibers, expanded afferent and efferent nerve terminals, increased microcirculatory bed capacity. The quantitative and qualitative shifts observed in NMS structure are morphologically equivalent to the rise in their functional potential, which forms the basis for the functional changes in conditions of increasing skeletal muscle hypertrophy.     

Synaptic morphology of the carotid body of the domestic fowl

Efferent and reciprocal synapses have been demonstrated in the carotid body of the domestic fowl (Gallus gallus domesticus). Synapses were also found with purely afferent morphology, but were probably components of reciprocal synapses. The general morphology of the endings suggested the presence of two types of axon, afferent axons making reciprocal and perhaps afferent synapses with Type I cells, and efferent axons making efferent synapses with Type I cells. A few axo-dendritic synapses were also found. The dense-cored vesicles associated with the afferent components of reciprocal synapses and with the possible true afferent synapses varied in diameter and core but could belong to one population of pre-synaptic vesicles. These observations are consistent wtih a new theory for the carotid body receptor mechanism. This proposes a spontaneously discharging afferent axon inhibited by an inhibitory transmitter substance released by the Type I cell via the "afferent" component of its reciprocal synapse, the "efferent" component inhibiting this release. Besides this chemoreceptor modulation of its afferent axon, the Type I cell may also have a general secretory function.     

Immunocytochemical and morphometric studies on the development of renin-immunoreactive cells in the rat kidney]

The development of renin-immunoreactive cells was immunocytochemically studied in Wistar-Imamichi rats. The renin-immunoreactivity was localized in the walls of the abdominal aorta, renal artery and arterioles in the kidney. The renin-immunoreactive cells converged with the progress of development from the renal artery via several arterioles to the afferent arteriole in the kidney. In the afferent arteriole, renin-immunoreactive cells appeared only in those of matured glomeruli. The matured glomerulus first appeared at 17 days of gestation followed by the initial appearance of renin-immunoreactive cells at 18 days. The juxtaglomerular index showing the relation between matured glomeruli and renin-immunoreactive cells increased rapidly until 20 days of gestation, shifted thereafter at a level similar to that at 20 days until 7 days after birth, and increased again until 20 days after birth. Although the area of the transverse section at the hilus of the kidney increased all through the period examined, the number of matured glomeruli increased rapidly from 17 days of gestation to 7 days after birth and maintained a fixed level thereafter. This led to the decrease in the number of matured glomeruli per unit area after 7 days after birth. The fine structure of renin-immunoreactive cells showed no difference according to their sites of localization.     

Effect of mesenteric vascular congestion on reflex control of renal blood flow

Portal hypertension initiates a splenorenal reflex, whereby increases in splenic afferent nerve activity and renal sympathetic nerve activity cause a decrease in renal blood flow (RBF). We postulated that mesenteric vascular congestion similarly compromises renal function through an intestinal-renal reflex. The portal vein was partially occluded in anesthetized rats, either rostral or caudal to the junction with the splenic vein. Portal venous pressure increased (6.5 +/- 0.1 to 13.2 +/- 0.1 mmHg; n = 78) and mesenteric venous outflow was equally obstructed in both cases. However, only rostral occlusion increased splenic venous pressure. Rostral occlusion caused a fall in RBF (-1.2 +/- 0.2 ml/min; n = 9) that was attenuated by renal denervation (-0.5 +/- 0.1 ml/min; n = 6), splenic denervation (-0.2 +/- 0.1 ml/min; n = 11), celiac ganglionectomy (-0.3 +/- 0.1 ml/min; n = 9), and splenectomy (-0.5 +/- 0.1 ml/min; n = 6). Caudal occlusion induced a significantly smaller fall in RBF (-0.5 +/- 0.1 ml/min; n = 9), which was not influenced by renal denervation (-0.2 +/- 0.2 ml/min; n = 6), splenic denervation (-0.1 +/- 0.1 ml/min; n = 7), celiac ganglionectomy (-0.1 +/- 0.3 ml/min; n = 8), or splenectomy (-0.3 +/- 0.1 ml/min; n = 7). Renal arterial conductance fell only in intact animals subjected to rostral occlusion (-0.007 +/- 0.002 ml.min(-1).mmHg(-1)). This was accompanied by increases in splenic afferent nerve activity (15.0 +/- 3.5 to 32.6 +/- 6.2 spikes/s; n = 7) and renal efferent nerve activity (32.7 +/- 5.2 to 39.3 +/- 6.0 spikes/s; n = 10). In animals subjected to caudal occlusion, there were no such changes in renal arterial conductance or splenic afferent/renal sympathetic nerve activity. We conclude that the portal hypertension-induced fall in RBF is initiated by increased splenic, but not mesenteric, venous pressure, i.e., we did not find evidence for intestinal-renal reflex control of the kidneys.