Renin-positive granulated Goormaghtigh cells

Summary It is difficult to distinguish between Goormaghtigh cells (G-cells) and media cells of the glomerular arterioles at the border of the Goormaghtigh cell field. Consequently, it has been unclear whether renin-positive G-cells are normally present and also whether renin-producing cells are recruited from the pool of renin-negative G-cells upon stimulation of the renin-angiotensin system (RAS). In the present study, immunohistochemical and electron-microscopic experiments have been carried out on serially sectioned kidney biopsies from four patients with pseudo-Bartter syndrome. The results strongly suggest that with longlasting stimulation of the RAS all renin-negative (secretory resting) G-cells are ultimately converted into renin-producing granular cells.Synonymous with extraglomerular mesangial cells     

Immunocytochemical and ultrastructural study of the frog (Rana pipiens) pars distalis with special reference to folliculo-stellate cell function during in vitro superfusion

Summary The colloidal gold immunocytochemical technique was used to determine the ultrastructural features of the glandular cells in the pituitaries of male frogs, Rana pipiens, both in vivo and after superfusion in vitro. Specific reactions to antisera against bullfrog gonadotropins, human prolactin, and synthetic 1–39 corticotropin allowed identification of the 3 corresponding types of glandular cells. No immunoreaction was obtained with antisera against human or ovine-growth hormone, human -thyrotropin hormone, and bovine S-100 protein. General morphological features of these immunocytochemically identified glandular cells were similar to those of equivalent cells previously described in other amphibian species. Non-glandular folliculo-stellate cells were distinctive. In freshly removed pituitaries, these folliculo-stellate cells contained lysosome-like structures, but did not show phagocytic vacuoles in the cytoplasm; they contained many mitochondria, and the Golgi complex and endoplasmic reticulum were relatively undeveloped. After 4 or 18 h of superfusion, some immunoreactive gonadotropic, prolactin, and corticotropic cells showed degeneration and destruction. In the same gland, folliculo-stellate cells retained a viable appearance, but showed phagocytic vacuoles containing secretory granule-like structures which were immunoreactive to gonadotropic, prolactin, and corticotropic antibodies. Some folliculo-stellate cells showed phagocytic vacuoles containing complete glandular cells. These results suggest that superfusion causes a destruction of some of the glandular cells, and that folliculo-stellate cells act as phagocytes when cellular debris or moribund cells are present in the intercellular space in the pituitary parenchyma.Supported by grant DCB 8710462 from the National Science Foundation, grant 2148-83 from the CAICYT (Spain) and the Junta de Andalucia (Spain)     

Specific adhesion between pheochromocytoma (PC12) cells and adrenal medullary endothelial cells in co-culture

Summary Chromaffin cells in the adrenal medulla are found in close proximity to capillary endothelial cells, thereby forming the classical endocrine complex. To examine the possible chemical basis of their interaction in more detail, we have grown bovine adrenal medullary endothelial (BAME) cells in monolayer cultures and added to them pheochromocytoma (PC12) cells, a chromaffin tumor cell line of rats. The PC12 cells were chosen because of the similarities they share with adrenal medullary chromaffin cells. PC12 cells rapidly attached to BAME cells cultures, their rate of adhesion being significantly enhanced over binding of PC12 cells to either uncoated plates or to monolayers of unrelated cell cultures. Consistent with this observation, we noted that the extracellular matrix (ECM) derived from the BAME cells did not enhance PC12 cell adhesion and did not promote neurite sprouting as previously described for ECM derived from corneal endothelial cells. The specific adhesion between PC12 and BAME cells could be abolished by cell surface extracts derived from these two cells but not by extracts derived from unrelated cell types. This activity was heat-labile, sensitive to trypsin and, to a lesser extent, to neuraminidase. We therefore conclude that PC12 cells may interact with BAME cells by specific proteinaceous adhesive factors associated with their plasma membranes. These interactions might represent the formative role of cell-cell contacts in the organization of the developing adrenal gland.Abbreviations BAME bovine adrenal medullary endothelial cells - DMEM Dulbecco's modified essential medium - ECM extracellular matrix - EMEM Eagle's modified essential medium - FCS fetal calf serum - PBS phosphate-buffered saline - PC12 rat pheochromocytoma cells     

Fine structure of a sensory organ in the arista of Drosophila melanogaster and some other dipterans

Summary The arista, a characteristic appendage of dipteran antennae, consists of 2 short segments at the base and a long distal shaft. A small sensory ganglion, from which arises the aristal nerve, is located proximally in the shaft. The fine structure of the aristal sensory organ was studied in detail in the fruitfly (Drosophila) and for comparison in the housefly (Musca) and the blowfly (Calliphora). In Drosophila, the aristal sense organ consists of 3 identical sensilla that terminate in the hemolymph space of the aristal shaft, and not in an external cuticular apparatus. Each sensillum comprises 2 bipolar neurons and 2 sheath cells; a third sheath cell envelops the somata of all six neurons of the ganglion. The neurons have long slender dendrites with the usual subdivision into an inner and an outer segment. One of the outer segments is highly lamellated and bears small particles (BOSS-structures) on the outside of its cell membrane; the other outer segment is unbranched and has a small diameter. The fine structure of the first dendrite is strongly reminiscent of thermoreceptors known from the antennae of other insects. These thermoreceptors are often coupled with hygroreceptors; however, we can only speculate whether the second dendrite of the aristal organ also has this function. Our present results argue against mechanoreceptive functions, as formerly postulated. The aristal sense organs in Musca and Calliphora are similar to those in Drosophila, but contain more sensilla (12 in Musca, 18 in Calliphora).     

Stereological and functional investigations on isolated adrenocortical cells: Zona fasciculata/reticularis cells of chronically ACTH-treated rats

Summary The morphology and function of isolated inner (zona fasciculata/reticularis) adrenocortical cells of rats pretreated with ACTH for 3, 6, 9 or 12 days were investigated. ACTH treatment induced a notable time-dependent enhancement in the steroidogenic capacity (corticosterone production) and growth of inner cells. The volumes of cells, mitochondrial compartment, membrane space [the cellular space occupied by smooth endoplasmic reticulum (SER) membranes] and lipid-droplet compartment, as well as the surface area of mitochondrial cristae and SER tubules, were increased in relation to the duration of ACTH pretreatment, and showed a highly significant positive linear correlation with both basal and stimulated corticosterone production. The acute exposure of isolated cells to ACTH provoked a striking lipid-droplet depletion, the extent of which was linearly and positively correlated with stimulated corticosterone secretion. The hypertrophy of the mitochondrial compartment and SER are interpreted as the morphological counterpart of the enhanced steroidogenic capacity of inner adrenocortical cells, inasmuch as the enzymes of steroid synthesis are located in these two organelles, and it is well known that chronic ACTH exposure stimulates the de novo synthesis of many of them in vivo. The rise in the number of lipid droplets, in which cholesterol is stored, is interpreted as being due to the fact that, under chronic ACTH treatment, the processes leading to cholesterol accumulation in adrenocortical cells (exogenous uptake and endogenous synthesis) exceed those of its utilization in basal steroid secretion. Cholesterol accumulated in lipid droplets as a reserve material may be rapidly utilized after acute ACTH exposure to meet the needs of the enhanced steroidogenic capacity of adrenocortical cells.     

Characterization of the follicles in the intermediate lobe of the pituitary gland of the Mongolian gerbil (Meriones unguiculatus)

Summary The Mongolian gerbil (Meriones unguiculatus) contains abundant follicles throughout the intermediate lobe (IL) of the pituitary gland in the adult animal. The mode of follicle formation, the nature of the follicle building cells and the distribution of follicles were investigated in semithin sections of the gerbil IL. The sections were stained conventionally, or immunohistochemically with antibodies directed against -melanocyte stimulating hormone (- MSH). Follicular cells were constantly -MSH-negative, and resembled the marginal cells lining the hypophyseal cleft with regard to their cytological and immunohistochemical properties. Moreover, follicular cells appeared to be derived from strands of marginal cells that regularly invaginated deep into the IL. Both follicular and marginal cells often made up cellular clusters. This process coincided with follicle formation and the generation or transport of the colloidal content found inside follicles and the hypophyseal cleft. Although the non-secretory cells of the IL obviously constituted one major source of pituitary colloid in the gerbil, -MSH-positive secretory cells, which occasionally were found to be discharged into the cleft cavity, might contribute to the colloidal contents.     

Morphological changes in the junctional complex of cells in the arachnoid layer of the rat after cold injury

Summary The junctional complexes of cells in the outer arachnoid layer overlying the cerebral cortex of 2-week-old rats were examined with freeze-fracture electron microscopy up to 60 min after transcranial cold injury to the dorsal surface of the brain. Within 30 min after injury, areas of gap and tight junctions with morphological features characteristic of junction formation and/or junction disruption were found scattered among normal junctional complexes in some arachnoid cells. Within 60 min after injury, tight junctions with features typical of less leaky zonulae occludentes were present in all arachnoid cells examined. These morphological features include increases in the number of tight junctional strands and the number of strand-to-strand anatomoses. Gap junctions were interspersed among the tight junctional strands, and many were completely encircled by the strands. The increase in the number and complexity of the tight junctional strands in response to brain injury may be the morphological basis for the maintenance of the cerebrospinal fluid-blood dural barrier.This study was supported by the National Institute of Neurological and Communicative Disorders and Stroke Grant NS20590. The opinions or assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the DoD or the USUHS. The experiments reported herein were conducted according to the principles set forth in the Guide for Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, National Research Council, DHEW Pub. No. (NIH) 78-23     

Abnormal expression ofα-L-fucosidase in lymphoid cell lines of fucosidosis patients

Fucosidosis is an autosomal recessive lysosomal storage disease due to a deficiency of-L-fucosidase activity in tissues and body fluids. Exponentially growing lymphoid cell cultures from four fucosidosis patients had 2.7-fold to 15.6-fold less extracellular-L-fucosidase protein and 28.8-fold to 144.0-fold less intracellular-L-fucosidase protein with negligible catalytic activity, compared to the mean of 19 control cultures. The percentage of total-L-fucosidase protein released extracellularly by cultures from the four patients was 64 to 85%, compared to 35±9% for control cultures. Intracellular and extracellular enzyme forms in fucosidosis and control cell lines were glycoproteins containing polypeptide chains ofM _r=52,000. During a 1.5-hr pulse-label with³⁵S-methionine,-L-fucosidase was synthesized by control cells and two fucosidosis cell lines as an intracellular form withM _r=58,000. During a subsequent 21-hr chase with unlabeled methionine, mutant enzyme was almost entirely processed to an extracellular form withM _r=62,000. In contrast, only 25–30% of control enzyme was processed to an extracellular form (M _r=62,000), with the remainder retained intracellularly (M _r=60,000). In the other two fucosidosis cell lines,-L-fucosidase was synthesized as an intracellular form withM _r=56,000 that was processed to an extracellular form withM _r=60,000. In summary, the fucosidosis mutation(s) affected the catalytic activity, quantity, and extracellular release of-L-fucosidase as expressed by lymphoid cells.This work was funded by NIH Grants DK 32161 to R. A. DiCioccio and GM 28428 to J. K. Darby.     

Thymic nurse cells: morphological study during their isolation from murine thymus

Summary Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of eleaved desmosomes confirmed that their aspect in vitro as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.A portion of this work was presented at the first Thymus Workshop. Rolduc, Netherlands, April, 1988     

Correlation of spinule dynamics and plasticity of the horizontal cell spectral response in cyprinid fish retina: quantitative analysis

Summary A negative feedback interaction between luminosity type horizonatal cells (HCs) and green-sensitive cones generates the long-wavelength-sensitive depolarizing response in biphasic chromaticity type HCs. This interaction is suppressed in the dark and is potentiated by light adaptation of the retina. HCs are morphologically plastic; during light adaptation, their dendritic terminals within cone pedicles extend, giving rise to spinules. This paper examines whether there is a quantitative correlation between the time course of light-dependent formation of the spinules and enhancement of the feedback interaction. The strength of the feedback interaction in isolated retinac of the roach was determined as the neutral wavelength at which reversal of spectral response polarity occurred in biphasic HCs. A good correlation was found between the neutral wavelength and the spinule/ribbon ratios of retinae. Biphasic HCs were intracellularly stained with horseradish peroxidase and the correlative ultrastructure of the contacted pedicles was examined. Neutral wavelength was found to be correlated with the spinule number, weighted according to the number of synaptic contacts mediating feed-forward transmission. The latter was estimated from the total number of labelled C_b/H2 HC processes (central and lateral) at synaptic triads. A model in which spinules mediate the negative feedback interaction of HCs in the retina of cyprinid fish is presented.