Small Granular Cells Research Articles

Light and Transmission Electron Microscopic Study of Olfactory Organ of Spotted Snakehead, Channa punctata (Bloch)

The olfactory organ of Channa punctata (Bloch) has been studied under light microscope and transmission electron microscope. The olfactory apparatus of C. punctata comprises of olfactory rosette, olfactory nerve, and olfactory bulb. Paired, oval shaped olfactory rosette present in the olfactory chamber on fish rostrum. Olfactory chamber opens externally via an anterior inlet and a posterior nostril outlet. Olfactory epithelium comprises of sensory and non-sensory regions. Sensory region is at basal part and non-sensory region is at proximal area of olfactory lamellae. In olfactory lamellae, sensory epithelium consists of olfactory receptor cells, supporting cells, basal cells, goblet cells, mucous cell and white cell. Olfactory receptor cells are of two types microvillous and ciliated. In C. punctata, olfactory bulb is sessile and is attached to the telencephalon. Cells of olfactory bulb are organized in four concentric layers. Outer layer is olfactory nerve layer formed by axons of olfactory receptor cells. Inner to it is glomerular layer where axons of olfactory receptor cells synapse with dendrites of mitral cells. Next towards deeper part is mitral cell layer which comprises larger multipolar mitral cells. Central core is formed by granular cell layer with small granular cells.

Distribution of Calcium-Binding Proteins and Cytochrome Oxidase Activity in the Projective Zone (Wulst) of the Pigeon Thalamofugal Visual Pathway: A Discussion in the Light of Current Concepts on Homology between the Avian Wulst and the Mammalian Striate (Visual) Cortex

This polemic article focuses on the current concepts of the architectonics of the hyperpallial projective zone (Wulst) in the avian thalamofugal visual pathway and the distribution of calcium-binding proteins parvalbumin (PV) and calbindin (CB), as well as cytochrome oxidase (CO) activity, in these brain regions of birds, including our histochemical and immunohistochemical data obtained on the pigeon. In the principal thalamorecipient sensory area of the Wulst, n. interstitialis hyperpallium apicale/hyperpallium intercalatum (IHA/HI), three discrete zones are identified: the two, containing punctate PV-ir neuropil and a densely packed population of mainly small PV-ir stellate and granular cells, and a single zone formed by punctate CB-ir neuropil and mainly CB-ir cells. The IHA/HI area is distinguished by a high CO activity. In the hyperpallium apicale (HA) and hyperpallium densocellulare (HD), PV-ir and CB-ir neurons of varied morphotypes are scattered diffusely throughout neuropil which is moderately immunoreactive to both calcium-binding proteins. These areas are characterized by the presence of large pyramidal-like and multipolar PV-ir and CB-ir neurons with long branched dendrites forming a cellular/fibrous layer in the superficial HA area. It is concluded that the thalamofugal visual pathway in the pigeon has two, PV- and CB-specific, channels. We draw a comparative analysis of the variability of these channels in different avian species, which is supposed to be due to variable ecological and adaptive factors. Within the current idea about the organization and evolutionary origin of the avian Wulst and the mammalian striate (visual) cortex, the homology between these brain structures is discussed.

Proteomic analysis and white spot syndrome virus interaction of mud crab (Scylla olivacea) revealed responsive roles of the hemocytes

White spot disease (WSD) is a highly virulent viral disease in shrimps. Clinical signs and high mortality of WSD is generally observed after a few days of infection by White Spot Syndrome virus (WSSV). Mud crabs are the major carrier and persistent host for the WSSV. However, an elucidation of viral interaction and persistent mode of WSSV infection in mud crab is still limited. We investigated the defensive role of mud crab (Scylla olivacea) hemocytes against WSSV infection by using comparative proteomic analysis coupled with electrospray ionization liquid chromatography tandem mass spectrometry (ESI-LC/MS/MS). The proteomic maps of expressed proteins obtained from WSSV infected hemocytes revealed differential proteins related to various biological functions, including immune response, anti-apoptosis, endocytosis, phosphorylation signaling, stress response, oxygen transport, molting, metabolism, and biosynthesis. Four distinctive cell types of crab hemocytes: hyaline cells (HC), small granular cells (SGC), large granular cells (LGC) and mixed granular cells (MGC) were found susceptible to WSSV. However, immunohistochemistry analysis demonstrated a complete replication of WSSV only in SGC and LGC. WSSV induced apoptosis was also observed in HC, SGC and MGC except for LGC. These results suggested that HC and MGC may undergo apoptosis prior to a complete assembly of virion, while SGC is more susceptible showing higher amplification and releasing of virion. In contrast, WSSV may inhibit apoptosis in infected LGC to stay in latency. This present finding provides an insight for the responsive roles of crustacean hemocyte cells involved in molecular interaction and defense mechanism against WSSV.

Evaluation of Neuroprotective Effect of Sevoflurane in Acute Traumatic Brain Injury: An Experimental Study in Rats.

To examine the effect of sevoflurane, a halogenated anesthetic used in clinical applications, on oxidative stress and inflammation after an acute traumatic brain injury (TBI) in rats. Thirty male Spragueâ€"Dawley rats were divided into three groups: control (Group 1), trauma (Group 2), and trauma+sevoflurane (Group 3). A diffuse TBI model was created for Groups 2 and 3. Sevoflurane anesthesia was applied 6 hours a day after induced trauma in Group 3. Glutathione (GSH), malondialdehyde (MDA), and tissue myeloperoxidase (MPO) activities were measured in the blood. Tumor necrosis factor alpha (TNF-±), vascular endothelial growth factor (VEGF), and Bax primary antibodies were used to determine the effects of TBI. MDA was significantly higher in Group 2 than in Group 1. There was a significant increase in tissue MPO levels in Groups 2 and 3 compared with those in Group 1. GSH levels decreased in Groups 2 and 3. Group 3 revealed degenerative changes in neurons and glial cells, vascular enlargement and congestion, and inflammatory cell infiltration around blood vessels. In Group 3, VEGF expression was positive in endothelial and inflammatory cells around blood vessels. Group 3 had positive TNF-± expression in neurons, small granular cells, and glial cells around blood vessels. Sevoflurane administration in acute TBI did not prevent the development of oxidative stress and inflammation.

Putative adult neurogenesis in two domestic pigeon breeds (Columba livia domestica): racing homer versus utility carneau pigeons.

Generation of neurons in the brains of adult birds has been studied extensively in the telencephalon of song birds and few studies are reported on the distribution of PCNA and DCX in the telencephalon of adult non-song learning birds. We report here on adult neurogenesis throughout the brains of two breeds of adult domestic pigeons (Columba livia domestica), the racing homer and utility carneau using endogenous immunohistochemical markers proliferating cell nuclear antigen (PCNA) for proliferating cells and doublecortin (DCX) for immature and migrating neurons. The distribution of PCNA and DCX immunoreactivity was very similar in both pigeon breeds with only a few minor differences. In both pigeons, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, walls of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and cerebellum. Generally, the olfactory bulbs and telencephalon had more PCNA and DCX cells than other regions. Two proliferative hotspots were evident in the dorsal and ventral poles of the lateral ventricles. PCNA- and DCX-immunoreactive cells migrated radially from the walls of the lateral ventricle into the parenchyma. In most telencephalic regions, the density of PCNA- and DCX-immunoreactive cells increased from rostral to caudal, except in the mesopallium where the density decreased from rostral to middle levels and then increased caudally. DCX immunoreactivity was more intense in fibres than in cell bodies and DCX-immunoreactive cells included small granular cells, fusiform bipolar cells, large round and or polygonal multipolar cells. The similarity in the distribution of proliferating cells and new neurons in the telencephalon of the two breeds of pigeons may suggest that adult neurogenesis is a conserved trait as an ecological adaptation irrespective of body size.

Kinetics of stress-induced trafficking of blood immune cells and alterations of viral shedding under the exposure of acute stressors in healthy human subjects

The stress of captivity could be the main reason for the loss of sperm quality of Litopenaeus setiferus (L) males in captivity. The aim of this study was focused on the physiological and immunological response of adult male shrimp exposed to a temperature extreme (33 °C) in order to understand how the stress modulates the physiological, immunological and reproductive behavior of L. setiferus males. We used some blood metabolic variables, sperm quality and immune response as indicators of stress measured daily during the 10-day experiment. The high temperature provoked loss of osmotic capacity (OC), a reduction in blood metabolites at day 5, a reduction in hemocyte pro Phenoloxidase (proPO) activity and a dramatic reduction in sperm quality in comparison to that observed in freshly captured wild shrimp populations. The ratio between proPO and granular cells (small granular and large granular cells) (proPO/GC) showed a cyclic behavior with lower peaks at days 3, 7 and 10 and high peaks at days 0, 5–6 and 8–9, evidencing migration and recovery of cells and proPO every 48–96 h, depending on the intensity of the stress. Such hemocyte migration was directed to the ampule and spermatophore where bacterial growth could be enhanced by abnormal and dead sperm cells. In such circumstances, a rapid mobilization of reserves could help to promote tissue regeneration in male testes and vas deferens. Such use of reserves could explain the reduction in blood metabolites observed at day 5 in present study. Although blood metabolites recovered after day 5, the loss of OC suggests that shrimp lose their osmotic homeostasis, possibly associated with the entrance of water due to inflammation of tissues provoked by melanization.

Two-dimensional segmentation of small convective patterns in radiation hydrodynamics simulations

Recent results from high-resolution solar granulation observations indicate the existence of a population of small granular cells that are smaller than 600 km in diameter. These small convective cells strongly contribute to the total area of granules and are located in the intergranular lanes, where they form clusters and chains. We study high-resolution radiation hydrodynamics simulations of the upper convection zone and photosphere to detect small granular cells, define their spatial alignment, and analyze their physical properties. We developed an automated image-segmentation algorithm specifically adapted to high-resolution simulations to identify granules. The resulting segmentation masks were applied to physical quantities, such as intensity and vertical velocity profiles, provided by the simulation. A new clustering algorithm was developed to study the alignment of small granular cells. This study shows that small granules make a distinct contribution to the total area of granules and form clusters of chain-like alignments. The simulation profiles demonstrate a different nature for small granular cells because they exhibit on average lower intensities, lower horizontal velocities, and are located deeper inside of convective layers than regular granules. Their intensity distribution deviates from a normal distribution as known for larger granules, and follows a Weibull distribution.

Characterization of the circulating hemocytes in mud crab (Scylla olivacea) revealed phenoloxidase activity

This study focused on an isolation and characterization of the circulating hemocytes in mud crab, Scylla olivacea. Isolation of specific cell types of hemocytes from crab hemolymph was accomplished by using 60% Percoll density gradient centrifugation. Four separated bands of the hemocytes were successfully obtained. Characterization of these isolated hemocytes by light microscope using trypan blue-rose bengal staining, rose bengal–hematoxilin staining, and phase contrast revealed four distinct types of hemocyte cells. Using their specific morphology and granularity, they were identified as hyaline cell (HC), small granular cell (SGC), large granular cell (LGC) and mixed granular cell (MGC). Transmission electron microscopy (TEM) revealed more details on specific cell size, size of cytoplasmic granule, and nuclear to cytoplasmic ratio, and confirmed the classification. Relative abundance of these cells types in the hemolymph of an adult crab were 15.50±8.22% for HC, 55.50±7.15% for SGC, 13.50±5.28% for LGC, and 15.50±3.50% for MGC. Proteomic analysis of protein expression for each specific cell types by two-dimensional electrophoresis identified two highly abundant proteins, prophenoloxidase (ProPO) and peroxinectin in LGC. Determination of phenoloxidase (PO) activity in each isolated cell types using in vitro and in situ chemical assays confirmed the presence of PO activity only in LGC. Based on an increased PO activity of crab hemolymph during the course of White Spot Syndrome Virus (WSSV) infection, these results suggest that prophenoloxidase pathway was employed for host defense mechanism against WSSV and it may link to the role of large granular hemocyte.

Function of mucilaginous secretions in the antibacterial immunity system of Eisenia fetida

Abstract The mucus layer on the skin surface of Eisenia fetida consists of several antimicrobial agents that provide a first line of defense against invading pathogens. The function of skin secretions in the antibacterial immunity system of this earthworm was confirmed for the first time in the present study. E. fetida individuals were immersed in a bacterial bath of Escherichia coli to induce antibacterial skin secretions. The secretions were found to be selective. After induction with E. coli, bacteriostasis of earthworm skin secretions after exposure to E. coli and Staphylococcus aureus increased significantly, especially towards S. aureus, although no bacteriostatic effect was observed after exposure to Pseudomonas aeruginosa. In addition, the up-cuticle protuberances and microfloccus in the up-cuticle dissociation surface may have important functions in the mucilaginous secretions of E. fetida. Furthermore, we found that earthworm gland cells in the epidermis, such as small granular proteinaceous cells, large granular orthochromatic mucous cells, and reticulation mucous cells, are responsible for the mucilaginous secretions. Our results suggest that mucilaginous secretions are an important defense in the antibacterial immunity system of E. fetida.

Intracellular oxidation by human glioma cell populations: effect of arachidonic acid

Arachidonic acid (AA) and Gamma linolenic acid have been shown to limit glioma cell growth, stimulate apoptosis and lipid peroxidation. However, brain tumours are characterised by cellular heterogeneity and responding cell populations have not been identified. Brain tumour samples from patients were disaggregated. In cell preparations from 7 gliomas, reactive oxygen species (ROS), morphology and plasma membrane integrity were monitored ±18–36 μM AA for 15–120 min using flow cytometry. Basal oxidative activity related to cell size/morphology, small granular cells showed lower activity. AA stimulation of ROS formation depended on cell size/morphology. Large, less granular cells showed greater AA stimulation. In 17 gliomas, GFAP immunofluorescence was demonstrated in larger cell populations. The large GFAP positive cell population with low side scatter was the highest responding cell population, suggesting selective tumour cell sensitivity to AA induced ROS formation. ROS may have a role in AA induced cell death and anti-tumour activity of AA in glioma.

Macro- and microstructural organization of the rabbit's celiac-mesenteric ganglion complex ( Oryctolagus cuniculus)

The macro- and microstructures of the rabbit celiac-mesenteric ganglion complex are described in 20 young animals. We found ten celiac ganglia, twenty-seven cranial mesenteric ganglia and eleven celiac-mesenteric ganglia. The celiac ganglia had a rectangular shape in nine cases (90%) and a circular one in one case (10%). The cranial mesenteric ganglia presented triangular (66.7%), rectangular (11.1%), L-shape (18.5%) and semi-lunar (3.7%) arrangements. The celiac-mesenteric ganglia were organized in three patterns: a single left celiac-mesenteric ganglion having a caudal portion (72.7%); celiac-mesenteric ganglia without a caudal portion (18.2%) and a single celiac-mesenteric ganglion with two portions: left and right (9.1%). The microstructure was investigated in nine celiac-mesenteric ganglia. The results showed that the celiac-mesenteric ganglion is actually a ganglion complex constituted of an agglomerate of ganglionic units separated by nerve fibers, capillaries and septa of connective tissue. Using the semi-thin section method we described the cellular organization of the celiac-mesenteric ganglion complex. Inside of each ganglionic unit, there were various cell types: principal ganglion neurons (PGN), glial cells (satellite cells) and SIF cells (small intensely fluorescent cells or small granular cells), which are the cytologic basis for each ganglionic unit of the rabbit's celiac-mesenteric ganglion complex.

Morphology and Immunological Roles of Hemocytes and Fixed Phagocytes in Black Tiger Shrimp Penaeus monodon

Morphology and immunological roles of the three distinct types of hemocytes, hyaline, small granular and large granular cells in black tiger shrimpPenaeus monodonwere studied. The study of functions of these hemocytes in the elimination of injected yeast (Saccharomyces cerevisiae) orVibrio harveyias foreign bodies showed a rapid response against those particles. Together with fixed phagocytes, the blood cells removed the yeast through the process of phagocytosis, nodule formation and encapsulation, which occurred at almost all parts of the body. The injection of the yeast caused a marked reduction in the blood cell counts in the hemolymph during the first 1 h.V. harveyiwas efficiently removed within 3 h after injection. The granular cells (small granular and large granular hemocytes) were the major blood cells that are associated with phenoloxidase activity. The role of hemocytes and fixed phagocytes on defense mechanism in the shrimp were discussed.

Haemolymph metabolic variables and immune response in Litopenaeus setiferus adult males: the effect of an extreme temperature

The stress of captivity could be the main reason for the loss of sperm quality of Litopenaeus setiferus (L) males in captivity. The aim of this study was focused on the physiological and immunological response of adult male shrimp exposed to a temperature extreme (33 °C) in order to understand how the stress modulates the physiological, immunological and reproductive behavior of L. setiferus males. We used some blood metabolic variables, sperm quality and immune response as indicators of stress measured daily during the 10-day experiment. The high temperature provoked loss of osmotic capacity (OC), a reduction in blood metabolites at day 5, a reduction in hemocyte pro Phenoloxidase (proPO) activity and a dramatic reduction in sperm quality in comparison to that observed in freshly captured wild shrimp populations. The ratio between proPO and granular cells (small granular and large granular cells) (proPO/GC) showed a cyclic behavior with lower peaks at days 3, 7 and 10 and high peaks at days 0, 5–6 and 8–9, evidencing migration and recovery of cells and proPO every 48–96 h, depending on the intensity of the stress. Such hemocyte migration was directed to the ampule and spermatophore where bacterial growth could be enhanced by abnormal and dead sperm cells. In such circumstances, a rapid mobilization of reserves could help to promote tissue regeneration in male testes and vas deferens. Such use of reserves could explain the reduction in blood metabolites observed at day 5 in present study. Although blood metabolites recovered after day 5, the loss of OC suggests that shrimp lose their osmotic homeostasis, possibly associated with the entrance of water due to inflammation of tissues provoked by melanization.

The role of the haematopoietic tissue in haemocyte production and maturation in the black tiger shrimp (Penaeus monodon)

The haematopoietic tissue (HPT) of the black tiger shrimp (Penaeus monodon) is located in different areas in the cephalothorax, mainly at the dorsal side of the stomach and in the onset of the maxillipeds and, to a lesser extent, towards the antennal gland. In young and in experimentally stimulated animals, the HPT is expanded in relatively larger and more numerous lobules throughout the cephalothorax. Four cell types could be identified in the HPT by electron microscopy. The type 1 cells are the presumed precursor cells that give rise to a large- and a small-granular young haemocyte, denominated as the type 2 and type 3 cells, respectively. A gradient of maturation from the type 1 towards the type 2 or 3 cells could frequently be observed. The presumed precursor cells are located towards the exterior of the lobules and maturing young haemocytes towards the inner part, where they can be released into the haemal lacunae. The type 4 cells show typical features of interstitial cells. Different stimulation experiments were carried out and various techniques were used to study the HPT in relation to the (circulating) haemocytes. The majority of the cells in the HPT are able to proliferate and proliferation can be increased significantly after the injection of saline and, to a much higher extent, after LPS injection. The circulating haemocytes of crustaceans are generally divided into hyaline (H), semigranular (SG) or granular (G) cells, of which large- and small-granular variants of each of these were suggested in the present study. Even after stimulation in this study, the circulating haemocytes scarcely divide. The high variations that were found in the total haemocyte count in the stimulation experiments were not accompanied by significant differences in differential haemocyte count and, therefore, appeared to be a less useful indicator of stress or health in P. monodon. Light and electron microscopical observations support the regulation of the populations of the different haemocyte types in the circulation by (stored) haemocytes from the connective tissue.In conclusion, according to morphological and immuno-chemical criteria, it is proposed in the present study to divide the haemocytes into a large and a small-granular developmental series. After extensive morphologicalobservations, it is suggested that the hyaline cells are the young and immature haemocytes of both the large- and small-granular cell line that are produced in the HPT, and can be released into the haemolymph. Indications were found that the granular cells, of at least the large-granular cell line, mature and accumulate in the connective tissue and are easily released into the haemolymph. Combining the results of the present study with literature, this proposed model for haemocyte proliferation, maturation and reaction will be discussed.

Ultrastructural localisation of NADPH-d/nNOS expression in the superior cervical ganglion of the hamster.

This study examined NADPH-d and nNOS expression in the SCG of hamsters. By light microscopy, numerous NADPH-d/NOS positive processes were widely distributed in the ganglion. Ultrastructurally, the NADPH-d reaction product was associated with the membranous organelles of neuronal soma, dendrites, myelinated fibres, small granular cells, and axon profiles bearing agranular vesicles. The NOS immunoreaction product, on the other hand, was localised in the cytoplasm of principal neurons and dendrites. Some of the NADPH-d/NOS labelled processes formed junctional contacts including synapses or zonulae adherentia. Compared with the neurons, the nonneuronal cells in the ganglion, namely, macrophages, satellite cells and endothelial cells were labelled by NADPH-d but devoid of nNOS immunoreaction product. The results suggest that the NADPH-d/NOS positive fibres in the SCG originate not only from the projecting fibres of the lateral horns of thoracic spinal cord, but also from the principal neurons and small granular cells; some may represent visceral afferent fibres. Electron microscopic morphometry has shown that about 67% of the principal neurons contain NADPH-d reaction product, and that the majority were small to medium sized neurons based on cross-sectional areas in image analysis. On the basis of the present morphological study, it is concluded NO is produced by some local neurons and possibly some nonneuronal cells in the SCG as well as some fibres of extrinsic origin. In this connection, NO may serve either as a neurotransmitter or neuromodulator.

Ultrastructure and Cytopathology of a Rickettsia-like Organism Causing Systemic Infection in the Redclaw Crayfish, Cherax quadricarinatus (Crustacea: Decapoda), in Ecuador

A studyof the ultrastructural characteristics of an intracellular bacterium infecting the redclaw crayfish, Cherax quadricarinatus, a pathogen referred to previously as a rickettsia-like organism (RLO), revealed the presence of different developmental stages. These included a rod-shaped and uniformly electron-dense elementary body (EB) and an intermediate body (IB). The length of the EB varied between 0.48 and 0.6 μm, and the diameter was 0.3 μm. The IB was 0.75 to 1.1 μm long by 0.36 to 0.44 μm in diameter. Although the EB of this bacterium has ultrastructural characteristics similar to those of Rickettsiella, no information is available regarding its genetic relationship to this genus, and the intracellular bacterium should continue to be referred to as a rickettsia-like organism. The hemocytes had different levels of infection, and the RLO proliferated inside these cells. The EB appeared to be free in the cytoplasm of infected hemocytes and other cells; however, this might be a fixation artifact. The EB was also contained in membrane-bound vacuoles along with the IB. RLO colonies were observed inside small granular cells. No large granular cells were observed in the sections examined; therefore, no data were obtained regarding infection of this type of hemocyte. The fixed phagocytes on the external side of the terminal hepatic arterioles had an activated interrupted layer containing RLO bacteria. Stem cells in the hematopoietic tissue were also infected, and some cells were apparently being released into circulation.

Immunohistochemical localization of calcium-binding proteins (CaBPs) in the epidermis of the earthworm Lumbricus terrestris (Annelida, Oligochaeta)

The present immunohistochemical study provides the first evidence of the presence of calcium-binding proteins (CaBPs) in the epidermis of the earthworm Lumbricus terrestris (Annelida, Oligochaeta) a lower invertebrate. The entire epidermis was labelled for calmodulin which is in agreement with its ubiquitous occurrence. Immunopositivity for calbindin D28K was limited to mucous cells, while that for S-100 protein was present only in neuroendocrine-like small granular cells. Finally, labelling for parvalbumin was specifically present in the subcutaneous nerve plexus. S-100 protein is considered to be a marker of neuroendocrine cells, at least in lower invertebrates such as Annelida. Although calbindin D28K is considered to be a marker of these cells in vertebrates, the same function cannot be attributed in Lumbricus terrestris. However, we can conclude that S-100 protein, as a regulatory protein, is phylogenetically older than calbindin D28K. We assume that the latter has an autoregulatory function in secretory processes. In agreement with previous data, we suggest that small granular cells exert a paracrine action in osmoregulatory and secretory processes.

Serotonin via 5‐HT1B and 5‐HT2B receptors stimulates anion secretion in the rat epididymal epithelium

1. The short-circuit current (Isc) technique was used to study the role of 5-hydroxytryptamine (5-HT) in the regulation of anion secretion in cultured rat cauda epididymal epithelia. 2. 5-HT, the 5-HT1B-selective agonist 5-nonyloxytryptamine (5-NOT) and the 5-HT2B-selective agonist alpha-methyl-5-hydroxytryptamine (alpha-methyl-5-HT) added basolaterally stimulated Isc in a dose-dependent manner with EC50 values of 0.4, 20 and 0.3 microM, respectively. No other agonists for 5-HT receptors had any effect. 3. The pattern of responses to 5-HT was biphasic. Pretreating the tissues with the 5-HT1B-selective antagonist isamoltane (200 microM) and the 5-HT2B-selective antagonist rauwolscine (200 microM) inhibited the rapid transient phase by 55 and 45 %, whereas the sustained phase could only be blocked by rauwolscine. 4. Removal of chloride or bicarbonate or both from the normal Krebs-Henseleit solution reduced the responses to 5-HT, 5-NOT and alpha-methyl-5-HT to varying degrees. The results suggest that 5-HT1B- and 5-HT2B-mediated responses were mainly due to chloride and bicarbonate secretion, respectively. 5. Manipulation of the cAMP and Ca2+ signal transduction pathways with chemical agents provided evidence that the responses to 5-HT were mediated through cAMP. 6. Piroxicam pretreatment abolished the Isc response to alpha-methyl-5-HT but not to 5-NOT, indicating that the 5-HT2B-mediated response, but not the 5-HT1B-mediated response, is dependent on prostaglandin synthesis. 7. Immunohistochemical studies showed that 5-HT-like immunoreactivity was detected in nerve fibres and in small granular cells surrounding the epididymal tubules. 8. It is suggested that the 5-HT released from serotonergic nerve endings and/or from mast cells regulates electrolyte and fluid secretion in the epididymis.

Pituitary adenomas and granular cell tumors. Incidence, cell type, and location of tumor in 100 pituitary glands at autopsy.

Incidentally detected pituitary adenomas were investigated in 100 pituitary glands at autopsy to determine the number, cell type, and location of tumors, and the presence of coexisting granular cell tumors in the neurohypophysis. Pituitary glands were sagittally sectioned at 1.5-mm intervals in toto and embedded in 1 cassette to orient location of each tumor. Twenty-four pituitary glands harbored adenomas, most smaller than 3 mm and the largest 6 x 5 x 4 mm. Two pituitary glands contained double adenomas of immunocytochemically different cell types. Of the 26 adenomas, 10 had lactotrophs, 2 had mixed lactotrophs-somatotrophs, 1 had mixed lactotrophs-luteinizing hormone cells, and 12 were nonfunctioning. One adenoma with adenocorticotropic hormone cells was also detected. Thus 25 of 26 (96%) adenomas were either lactotrophic or nonfunctioning; this percentage is much higher than that of surgically resected tumors. Twenty-two tumors were contiguous with or adjacent to the capsule from which the adenomas originated. Nine granular cell tumors were noted in the neurohypophysis; 3 coexisted with pituitary adenomas. Fourteen additional cases revealed small granular cell nests. Thus the incidental finding of nonfunctioning pituitary adenomas is relatively common in adults (24% of cases in this study), and the coexistence of pituitary adenomas and granular cell tumors may suggest a possible histogenic connection between anterior and posterior pituitary tumorigenesis.

Ultrastructural and Cytochemical Characteristics of Phagocytes in Kuruma Prawn.

Five types of phagocytes were observed in kuruma prawn Penaeus japonicus. Two of them were fixed phagocytes and three were hemocytes. Fixed phagocytes were detected in the heart and lymphoid organ. Phagocytes in the heart were observed on basal lamina covering sarcolemma of heart muscles and the cells had many lysosomal granules (0.1 μm in diameter). Phagocytes in the lymphoid organ was characterizedby numerous interdigitating cell processes and few cytoplasmic granules. The hemocytes were classified into three types, hyaline cell (HC), small granular cell (SGC) and large granular cell (LGC), according to the presence of cytoplasmic deposit and size of granules. The HC had cytoplasmic deposits and a few small granules (0.2 μm in diameter). The SGC had small granules (0.2 μm in diameter) but the LGC contained large granules (1 μm in diameter). Lysosomal enzymes, such as acid phosphatase, β-glucuronidase and α-naphthyl butylate esterase, were detected in all five phagocytic cell types. Esterase activity was higher in the LGC than in any other phagocytes. Peroxidase activity was also detected in all phagocytes, although it was weak. Prophenoloxidase activity was found only in the SGC and LGC. These results indicate that the fixed phagocytes are different from the hemocytes both in their ultrastructural and cytochemical characteristics.