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Exocrine Glands (exocrine + gland)
Selected AbstractsA novel exocrine gland in the trochanter of ant legsACTA ZOOLOGICA, Issue 3 2008Johan Billen Abstract We found a hitherto unknown gland in the trochanter of several ant species. The gland occurs at the proximal ventral part of the trochanter in all legs. It consists of a thickening of the tegumental epithelium, the lining cuticle of which is characterized by narrow vertical pores that lead the secretion to the outside. Its function is probably that of producing lubricant substances to allow optimal manoeuvrability of the articulation between the trochanter and the coxa. [source] Functional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.)ACTA ZOOLOGICA, Issue 2 2006Dieter Eelen Abstract Eelen D., Børgesen L.W. and Billen J. 2006. Functional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.). ,Acta Zoologica (Stockholm) 87: 101,111 The postpharyngeal gland (PPG) is unique to ants and is the largest exocrine gland in their head. In queens of the pharaoh's ant, Monomorium pharaonis, the gland contains approximately 15 finger-like epithelial extensions on each side and opens dorsolaterally in the posterior pharynx. In these ants the PPG morphology varies considerably according to age and mating status. The epithelial thickness increases with age and reaches a maximum at 3 weeks in both virgin and mated queens. A considerable expansion of the lumen diameter occurs in both groups between 4 and 7 days. Virgin queens release their secretion into the gland lumen from an age of 7 days, whereas mated queens accumulate large amounts of secretion in their epithelium. The increasing epithelial thickness, together with the increasing lumen diameter, the presence of numerous inclusions in the epithelium and the release of secretion, are indicative for increasing gland activity. The gland ultrastructure indicates involvement in lipid metabolism and de novo synthesis of lipids. The PPG of workers consists of 12 finger-like tubes at each side. There is a significant difference in epithelial thickness between nurses and repletes and between nurses and foragers. We suggest the PPG serves different purposes in pharaoh's ants: it is likely that the PPG of workers and virgin queens is used to feed larvae. In mated queens the gland probably plays a role in providing the queen with nutritious oils for egg production. The PPG may also function in signalling species nestmate and caste identity, as well as in the reproductive capacity of the queens. [source] The subepithelial gland in ants: a novel exocrine gland closely associated with the cuticle surfaceACTA ZOOLOGICA, Issue 4 2003Bruno Gobin Abstract Two glandular systems were discovered that secrete their products onto the cuticular surface in ants. The first, the subepithelial gland, was previously undescribed in ants, and is found throughout the body just beneath the epithelium. This gland consists of independent secretory units, each made up of a single gland cell and an associated duct cell that penetrates the cuticle. Its ultrastructural appearance is consistent with possible hydrocarbon production. Examining 84 ant species, the subepithelial gland was found in eight subfamilies (out of 13), although not necessarily in all species. In a single ant species, Harpegnathos saltator, it was the epithelium itself that was enlarged and functioned as a gland. The enlarged epithelial cells secrete their products directly onto the cuticle through distinct cuticular crevasses. [source] Prostate cancer: a newly discovered route for testosterone to reach the prostateANDROLOGIA, Issue 5 2009Treatment by super-selective intraprostatic androgen deprivation Summary The prostate, an androgen-regulated exocrine gland, is an integral part of the male reproductive system which has an essential function in sperm survival and motility in its long hostile route to meet and fertilise the egg in the Fallopian tube. Testosterone is known to be the key, obligatory regulator of the prostate that promotes the development and progression of prostate cancer (PCa). Yet, the pathophysiological mechanism of PCa remains unclear and its causal relation to serum testosterone has not been established. Here, we report on the discovery of a previously unrecognized route of flow of free testosterone (FT), at a concentration of 130 times the physiological levels, reaching the prostate via the testicular and prostate venous drainage systems, bypassing the systemic circulation. This condition results from the malfunction of the vertically oriented testicular venous drainage system in humans, a phenomenon with a prevalence that increases rapidly with age, which causes deviation of the testicular venous flow from its normal route. Early results of an interventional radiological procedure, super-selective intraprostatic androgen deprivation therapy are discussed. This treatment has resulted in decrease in prostate volume, and serum PSA, with disappearance of cancerous cells on repeat biopsies in five of six patients. Some of the unresolved biological enigmatic questions associated with PCa are discussed. We conclude that pathological flow of FT from the testes directly to the prostate in an extremely high concentration via the testicular-prostate venous drainage systems was identified may explain the mechanism for the development of PCa. We suggest a time-window for eradication of localised, androgen-sensitive, PCa cells. We anticipate that this treatment may retard, stop or even reverse the development of the disease. A mechanism for the evolution of PCa is discussed. [source] Reversal of benign prostate hyperplasia by selective occlusion of impaired venous drainage in the male reproductive system: novel mechanism, new treatmentANDROLOGIA, Issue 5 2008Y. Gat Summary The prostate is an androgen-regulated exocrine gland producing over 30% of the noncellular components of the semen and promoting optimal conditions for survival and motility of sperm in the vagina. Benign prostate hyperplasia (BPH) is the most common benign neoplasm in men. Its aetiology is not clear, and therefore, current medical treatments are directed towards the symptoms. Though testosterone is known to be the promoter of prostate cell proliferation, no causal relation between serum testosterone levels and BPH has been found. In this study, we propose a novel and tested pathophysiological mechanism for the evolution of BPH and suggest a tested and effective treatment. We found that in all BPH patients, the one-way valves in the vertically oriented internal spermatic veins are destroyed (clinically manifested as varicocele), causing elevated hydrostatic pressure, some 6-fold greater than normal, in the venous drainage of the male reproductive system. The elevated pressure propagates to all interconnected vessels leading to a unique biological phenomenon: venous blood flows retrograde from the higher pressure in the testicular venous drainage system to the low pressure in the prostatic drainage system directly to the prostate (law of communicating vessels). We have found that free testosterone levels in this blood are markedly elevated, with a concentration of some 130-fold above serum level. Consequently, the prostate is exposed to: (i) increased venous pressure that causes hypertrophy; (ii) elevated concentration of free testosterone causing hyperplasia. We have treated 28 BPH patients using a technique that restores normal pressure in the venous drainage in the male reproductive system. The back-pressure and the back-flow of blood from the testicular to the prostate drainage system were eliminated and, consequently, a rapid reduction in prostate volume and a regression of prostate symptoms took place. [source] Cysteine-rich secretory proteins are not exclusively expressed in the male reproductive tractDEVELOPMENTAL DYNAMICS, Issue 11 2008Thulasimala Reddy The Cysteine-RIch Secretory Proteins (CRISPs) are abundantly produced in the male reproductive tract of mammals and within the venom of reptiles and have been shown to regulate ion channel activity. CRISPs, along with the Antigen-5 proteins and the Pathogenesis related-1 (Pr-1) proteins, form the CAP superfamily of proteins. Analyses of EST expression databases are increasingly suggesting that mammalian CRISPs are expressed more widely than in the reproductive tract. We, therefore, conducted a reverse transcription PCR expression profile and immunohistochemical analyses of 16 mouse tissues to define the sites of production of each of the four murine CRISPs. These data showed that each of the CRISPs have distinct and sometimes overlapping expression profiles, typically associated with the male and female reproductive tract, the secretory epithelia of exocrine glands, and immune tissues including the spleen and thymus. These investigations raise the potential for a role for CRISPs in general mammalian physiology. Developmental Dynamics 237:3313,3323, 2008. © 2008 Wiley-Liss, Inc. [source] Ultrastructural identification of the antennal gland complement in Siagona europaea Dejean 1826, a myrmecophagous carabid beetleACTA ZOOLOGICA, Issue 3 2005Anita Giglio Abstract We examined antennal exocrine glands in adults of a myrmecophagous carabid beetle, Siagona europaea Dejean 1826 (Coleoptera, Carabidae), by light and electron microscopy and we identified two types of integumentary glands. The first type includes glands formed by three cells (a secretory cell, an intercalary cell and a duct cell) known as class 3 of Noirot and Quennedey (1991). The secretory cell has several large multivesicular electron-lucent bodies, indicating a glycoprotein product associated with lipids. We hypothesize that this secretion protects the surface of antennae and sensilla from wear. The second group of glands includes unicellular glands known as oenocytes (class 2 of Noirot and Quennedey, 1991), which secrete epicuticular hydrocarbons through epidermal cells. [source] Accumulation of amyloid-, protein in exocrine glands of transgenic mice overexpressing a carboxyl terminal portion of amyloid protein precursorINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2000Ken-Ichiro Fukuchi Amyloid-, protein (A,) and its precursor (,PP) play important roles in the pathogenesis of Alzheimer disease and inclusion-body myositis. In humans, A, deposits are found in brain, skeletal muscle, and skin. Therefore, we have investigated possible A, deposits in multiple tissues of two transgenic mouse lines overexpressing the signal plus A,-bearing 99-amino acid carboxyl terminal sequences of ,PP under the control of a cytomegalovirus enhancer/,-actin promoter. One of the lines developed A,-immunoreactive intracellular deposits consistently in the pancreas and lacrimal gland, and occasionally in gastric, DeSteno's, and lingual glands. Although the A, deposits increased during ageing and degenerative changes of the tissues were observed, little or no extracellular A, deposits were observed up to the age of 25 months. These lines of transgenic mice are useful for studying the molecular mechanisms of development and clearance of intracellular A, deposits. [source] Primary Gougerot,Sjögren syndrome: a dermatological approachJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 3 2006A-M Roguedas Abstract Gougerot,Sjögren syndrome (GSS) is a chronic heterogeneous non-organ-specific autoimmune disease, encompassing a wide spectrum of clinical manifestations. It is characterized by a lymphocytic infiltration of the exocrine glands, also called epitheliitis, resulting in xerostomia and keratoconjunctivitis sicca. The skin can also be involved; for example, xerosis is a consequence of epitheliitis. Dermatological consequences of polyclonal reactivity are vasculitis and manifestations of B-cell proliferation vary from plasma cell infiltrates to B-cell lymphoma. [source] Chemical ecology of triatomine bugs: vectors of Chagas diseaseMEDICAL AND VETERINARY ENTOMOLOGY, Issue 4 2001L. Cruz-López Abstract. Knowledge of chemical ecology of haematophagous triatomine bugs (Hemiptera: Heteroptera: Reduviidae) could be of practical value because this polyphyletic subfamily includes species of medical importance, such as vectors of Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae), the aetiological agent of Chagas disease. For particular species of Dipetalogaster, Panstrongylus, Rhodnius and Triatoma, therefore, we review information on exocrine glands and products, interpreting their apparent roles as semiochemicals in the aggregation, alarm, defence, host-finding and sexual behaviour of these Triatominae. [source] Occurrence of antennal glands in antsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 11 2008Robert Renthal Abstract A previous report of the discovery of exocrine glands in the antennal club of queens and workers of Solenopsis invicta Buren, 1972 left open the question of the extent to which similar glands occur in the Formicidae family. We wanted to know if these antennal glands are unique to Solenopsis, or they are found in a wider taxonomic group. Using scanning electron microscopy, we examined the antennae of 41 ant species. Presence of the antennal glands was indicated by a characteristic circumferential ring of pores in a distal antennal segment of workers. Pores were found in the 9th antennal segment of all 26 species of Solenopsis examined. Pores were absent in the following: Monomorium minimum, M. pharaonis, Pheidole sp., Crematogaster sp., Linepithema humile, Forelius sp., Dorymyrmex sp., Paratrechina sp., Oecophylla smaragdina, Campanotus sp., Ectatomma ruidum, E. tuberlatum, and Pseudomyrmex ferruginea. However, pores were found in the antennal club of Tetramorium bicarinatum workers and queens. After KOH digestion of T. bicarinatum antennae, internal canals were observed in both workers and queens, and the canals are connected to spherical reservoirs in queens. T. bicarinatum was the only non- Solenopsis species examined, which showed evidence for antennal glands in the distal funiculus. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc. [source] Effect of P2X7 receptor knockout on exocrine secretion of pancreas, salivary glands and lacrimal glandsTHE JOURNAL OF PHYSIOLOGY, Issue 18 2010Ivana Novak The purinergic P2X7 receptors are expressed in different cell types where they have varied functions, including regulation of cell survival. The P2X7 receptors are also expressed in exocrine glands, but their integrated role in secretion is unclear. The aim of our study was to determine whether the P2X7 receptors affect fluid secretion in pancreas, salivary glands and tear glands. We monitored gland secretions in in vivo preparations of wild-type and P2X7,/, (Pfizer) mice stimulated with pilocarpine. In cell preparations from pancreas, parotid and lacrimal glands we measured ATP release and intracellular Ca2+ activity using Fura-2. The data showed that pancreatic secretion and salivary secretions were reduced in P2X7,/, mice, and in contrast, tear secretion was increased in P2X7,/, mice. The secretory phenotype was also dependent on the sex of the animal, such that males were more dependent on the P2X7 receptor expression. ATP release in all cell preparations could be elicited by carbachol and other agonists, and this was independent of the P2X7 receptor expression. ATP and carbachol increased intracellular Ca2+ activity, but responses depended on the gland type, presence of the P2X7 receptor and the sex of the animal. Together, these results demonstrate that cholinergic stimulation leads to release of ATP that can via P2X7 receptors up-regulate pancreatic and salivary secretion but down-regulate tear secretion. Our data also indicate that there is an interaction between purinergic and cholinergic receptor signalling and that function of the P2X7 receptor is suppressed in females. We conclude that the P2X7 receptors are important in short-term physiological regulation of exocrine gland secretion. [source] Metastatic myoepithelioma of the breastANZ JOURNAL OF SURGERY, Issue 12 2004Ross R. Jennens Myoepitheliomas are typically benign tumours arising from exocrine glands. There have only been five reports of malignant myoepitheliomas from breast origin previously published in the English literature. This report describes a patient with myoepithelioma arising in the breast which later metastasized despite the primary tumour having benign histological features. Impaired immune function due to end-stage renal failure and haemodialysis may have contributed to the malignant potential of her tumour. The literature regarding myoepithelial tumours is reviewed. All breast myoepitheliomas should be managed as potentially malignant tumours with appropriate surgical clearance and staging. [source] Human Tissue Distribution of TA02, Which is Homologous with a New Type of Aspartic Proteinase, Napsin ACANCER SCIENCE, Issue 10 2000Takashi Hirano The N-terminal amino acid sequence of TA02 (molecular weight 35.0 kDa, isoelectric point 5.29), which is associated with primary lung adenocarcinoma, was determined and a fragment peptide was used to generate mouse monoclonal antibodies (mAbs) against TA02. The amino acid sequence suggested that TA02 might be homologous with napsin A, a new type of aspartic proteinase. In this context, we confirmed the expression of napsin A in primary lung adenocarcinoma using reversetranscription polymerare chain reaction (RT-PCR) and showed that the TA02 mAbs reacted with glutathione-S-transferase (GST)-napsin A fusion protein. We concluded that TA02 is the same molecule as napsin A, and showed immunohistochemically that it is distributed mainly in type II pneumocytes, alveolar macrophages, renal tubules and exocrine glands and ducts in the pancreas. In particular, type II pneumocytes and alveolar macrophages showed high expression of TA02 among human normal tissues. In primary lung adenocarcinoma, 47 out of 58 (81.0%) primary lesions were positive. All well-differentiated adenocarcinomas except those of goblet cell type showed high expression of TA02. In addition, two out of seven (28.6%) large cell carcinomas showed low expression of TA02. The other histopathological types of primary lung cancer did not express TA02 at all. A few cases of renal cell cancer, pancreatic cancer, breast cancer, thyroid cancer, colon cancer and ovarian cancer showed low expression, but the staining patterns were completely different from that of primary lung adenocarcinoma, which showed a granular staining pattern. Our novel mAbs should be valuable for immunochemical detection of TA02/napsin A. [source] Local dynamic changes in confined extracellular environments within organsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2009Natasha Behrendorff Summary 1Herein we review past work that has studied the composition of luminal fluid in organs, with a focus on measures of calcium and pH in the exocrine glands. This luminal environment is ,external' to the mammalian body and is not subject to the usual mechanisms of homeostatic control. Instead, it is controlled by the behaviour of the cells that line the lumen. 2We discuss the likely possibility that rapid and local changes in calcium and pH occur within microdomains in the lumen. Further, we present preliminary evidence, using live cell imaging of intact pancreatic fragments, that supports the idea that pH changes do occur. Our evidence indicates that exocytosis of secretory granules in pancreatic acinar cells leads to a loss of protons from the granule and a subsequent local acidification of the lumen. 3These changes in luminal composition are placed in the context of diseases of the pancreas, such as cystic fibrosis and pancreatitis, both of which are known to result in perturbations of luminal fluid composition. [source] Purinergic regulation of the epithelial Na+ channelCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2009Lauren M O'Mullane Summary 1. The epithelial Na+ channel (ENaC) is a major conductive pathway that transports Na+ across the apical membrane of the distal nephron, the respiratory tract, the distal colon and the ducts of exocrine glands. The ENaC is regulated by hormonal and humoral factors, including extracellular nucleotides that are available from the epithelial cells themselves. 2. Extracellular nucleotides, via the P2Y2 receptors (P2Y2Rs) at the basolateral and apical membrane of the epithelia, trigger signalling systems that inhibit the activity of the ENaC and activate Ca2+ -dependent Cl, secretion. 3. Recent data from our laboratory suggest that stimulation of the P2Y2Rs at the basolateral membrane inhibits ENaC activity by a signalling mechanism that involves G,, subunits freed from a pertussis toxin (PTX)-sensitive G-protein and phospholipase C (PLC) ,4. A similar signalling mechanism is also partially responsible for inhibition of the ENaC during activation of apical P2Y2Rs. 4. Stimulation of apical P2Y2Rs also activates an additional signalling mechanism that inhibits the ENaC and involves the activated G, subunit of a PTX-insensitive G-protein and activation of an unidentified PLC. The effect of this PTX-insensitive system requires the activity of the basolateral Na+/K+/2Cl, cotransporter. [source] | |||||||||||||