Interlobular Areas Research Articles

Identification, culture, and characterization of pancreatic stellate cells in rats and humans

Background & Aims: Until now, the basic matrix-producing cell type responsible for pancreas fibrosis has not been identified. In this report, retinoid-containing pancreatic stellate cells (PSCs) in rat and human pancreas are described, and morphological and biochemical similarities to hepatic stellate cells are shown. Methods: Electron and immunofluorescence microscopy (collagen types I and III, fibronectin, laminin, α-actin, and desmin) was performed using pancreatic tissue and cultured PSCs. Extracellular matrix synthesis was shown using quantitative immunoassay and Northern blot analysis. Results: PSCs are located in interlobular areas and in interacinar regions. Early primary cultured PSCs contain retinol and fatty acid retinyl-esters. Addition of retinol to passaged cells resulted in retinol uptake and esterification. During primary culture, the cells changed from a quiescent fat-storing phenotype to a highly synthetic myofibroblast-like cell expressing iso-α-smooth muscle actin (>90%) and desmin (20%–40%) and showing strong positive staining with antibodies to collagen types I and III, fibronectin, and laminin. As determined on protein and messenger RNA level, serum growth factors stimulated the synthesis of collagen type I and fibronectin. Conclusions: The identification of PSCs, particularly in fibrotic areas, and the similarities of these cells to hepatic stellate cells suggest that PSCs participate in the development of pancreas fibrosis. GASTROENTEROLOGY 1998;115:421-432

Immunohistochemical study of leucine-enkephalin and its secretory effects in the isolated pig lacrimal gland.

In our previous studies immunohistochemical studies have demonstrated the presence of leucine-enkephalin (Leu-Enk) in the intrinsic nerves of the pig lacrimal gland, which are discernible in the interlobular and interacinar areas from where branches that innervate the acinar tissues are sent. Since the intrinsic nerves have been shown to contain Leu-Enk, this study aimed to investigate the secretory effects of this neuropeptide in isolated segments of the pig lacrimal gland and to reconfirm its presence in the neuronal tissue of the lacrimal gland. Leu-Enk was identified using immunohistochemical techniques, while total protein output was measured in the effluent samples by an automated on-line colorimetric method. The Ca2+ and Mg2+ concentrations in the effluent samples were determined using an atomic absorbance spectrophotometer. Leu-Enk (10(-12)-10(-7) M) evoked marked increases in total protein output from superfused lacrimal gland segments. The secretory effect of Leu-Enk was not blocked by pretreatment of the tissue with atropine but was substantially reduced by a combination of phentolamine and propranolol. The competitive antagonist, naloxone, has no effect on basal protein output, but when combined with Leu-Enk it caused a significant reduction in total protein output. Combining theophylline (10(-3) M) with Leu-Enk resulted in a marked potentiation of total protein output. In superfused lacrimal gland segments Leu-Enk (10(-8) M) evoked a net efflux of magnesium (Mg2+ release) and a net influx of calcium (Ca2+ intake). The results indicated a physiological role for Leu-Enk in the regulation of protein secretion in the pig lacrimal gland.

Immunohistochemical identification of galanin and leucin-enkephalin in the porcine lacrimal gland

The presence and distribution of galanin (GAL) and leucine-enkephalin (LEU-ENK) in the pig lacrimal gland was investigated using immunohistochemical techniques.Lacrimal gland segments obtained from the abattoir were fixed in paraformaldehyde-picric acid solution, cut into 40–50 μm thick sections and processed for immunohistochemistry using polyclonal antisera against GAL and LEU-ENK. GAL- and LEU-ENK-immunoreactive intrinsic multipolar neurons were observed in the interacinar and interlobular areas of the pig lacrimal gland. From these regions these intrinsic neurons send branches to the acinar and other tissues of the gland. Immunoreactivity was confined solely to the neural elements. These two potent biologically active neuropeptides may play important roles in the regulation of lacrimal fluid secretion.

A Histopathological Study on Ventral and Dorsal Pancreas Tissues in Patients with Pancreas Divisum

Abstract: Five cases of pancreas divisum, clinically diagnosed by endoscopic retrograde choledochopancreatography (ERCP), were studied histopathologically. They consisted of four biopsied cases and one patient who underwent pancreatoduodenectomy under the diagnosis of a suspected pancreatic carcinoma. Fibrosis was found in three out of the five cases, two cases with fibrosis in the dorsal pancreas and one in the ventral pancreas. In the two dorsal fibrosis pancreas cases, fibrosis was distributed in the intra‐ and interlobular areas and was accompanied by atrophy or disappearance of the acinar cells. These findings were compatible with chronic obstructive pancreatitis, distal to a stricture of the pancreatic duct. In the one ventral fibrosis pancreas case, i. e., the pancreatoduodenectomized case, fibrosis was distributed mainly in the interlobular area associated with hemosiderin deposition. Hemosiderin deposition was also observed in inflammatory foci at the posterior aspect of the ventral pancreas. Hence, such interlobular fibrosis developed in relation to the inflammatory foci, and was not caused by pancreas divisum. Therefore, in pancreas divisum, abnormal findings were observed in the dorsal pancreas tissue, and they were compatible with chronic obstructive pancreatitis. (Dig Endosc 1994; 6 : 74–79)

Histotopographic and Ultrastructural Study on the Lymphatic Network of the Pancreas in the Guinea Pig

The localization of absorbing lymph vessels was studied in the normal guinea pig pancreas by light microscopy (serial semithin sections) and transmission electron microscopy (ultrathin sections). Absorbing lymph vessels were observed both in the interlobular and intralobular areas where they can be localized close to the adenomeres. Lymph vessels were also seen in the interlobular areas located next to the islets of Langerhans and to groups of endocrine cells (n = 8-10) not showing a vascular organization comparable with islets of Langerhans. All lymph vessels in the pancreas are absorbing lymph vessels, characterized by a very thin endothelial wall, anchoring filaments and the absence of a definitive basal membrane. Adjacent endothelial cells form end-to-end, overlapping and interdigitating intercellular junctions. Valves were present both in the interlobular and intralobular lymph vessels.

Localization of vasoactive intestinal peptide binding sites in the thymus and bursa of Fabricius of the chick

The purpose of this study was to determine the distribution of VIP binding sites in the thymus and bursa of Fabricius using receptor binding and autoradiographic techniques. Biochemical characterization of 125I-VIP binding sites determined two classes of specific binding sites in both tissues. The dissociation constants determined in the thymus were 1.12 nM and 88.5 nM, and in the bursa were 0.459 nM and 70.8 nM. Autoradiographic localization of 125I-VIP binding sites within the thymus demonstrated specific binding associated with the medullary region of the thymic lobule and the blood vessels in the interlobular and trabecular areas. Within the bursa of Fabricius, high densities of silver grains corresponded with vascular elements in the interfollicular regions, the epithelial border of the plicae, the muscular layer surrounding the organ, and the diffusely infiltrated area near the burso-cloacal duct.

The renal cortical lymphatic system in dogs with unimpeded lymph and urine flow.

The distribution and extent of the lymphatic circulation in the renal cortex was analyzed in three dogs under conditions of unimpeded lymph and urine flow. The kidneys were drip fixed with acrolein in vivo, and cortical tissue strips were prepared for light and electron microscopic examination. Analysis of 90 tissue strips revealed 38 cortical lymphatics, one third of which were intralobular in position. The intralobular lymphatic capillaries were related primarily to tubules, afferent arterioles, or renal corpuscles. The remainder of the lymphatics were located in interlobular connective tissue areas in association with the interlobular blood vessels. Interlobular lymphatics had a surface area twice that of intralobular vessels. Stereological analysis was used to estimate the volume density of the components of the renal cortex. The volume density of lymphatics was found to be 0.0014, but because of the relative infrequency of lymphatics, this value was considered to be approximate. The volume density data for non-lymphatic renal components were found to be in close agreement with published data. From these volume density values it was concluded that the volume of cortical lymph in a functioning dog kidney is equivalent to about 1% of the volume of blood in the cortical peritubular capillaries.

The villous stems of the human placenta.

Dissection and graphic reconstruction of villous stems of human placentas has shown that the allegedly typical pattern, namely, one single villous stem and one maternal arterial ostium supplying each lobule, is not the usual state. More often, portions of one villous stem supply several lobules, and several stems take part in the formation of one lobule. This, together with the previously demonstrated location of arterial ostia at the interlobular areas, leads to the concept that arterial ostia, usually in close association with large anchoring villi, form a network at the base of the placenta which determines the distribution of the lobules.

Lobular structure of hemochorial primate placentas, and its relation to maternal vessels.

AbstractStructure of the placental lobule and its topographic relation to the ostia of maternal vessels were studied in primates with hemochorial placentas. The lobule contains most of the terminal villi, whereas stems predominate in interlobular areas. The placenta of Tarsiidae consists of one lobule supplied by one maternal artery. Ceboidea (New World Monkeys) have multilobular placentas. In both forms arteries reach the intervillous space below the center of a lobule, and then continue into the lobule as perforated, branched channels which lose their maternal vessel wall. In Cercopithecoidea (Old World Monkeys) each maternal artery has a convolution in the decidua below an interlobular area, then continues straight to a point below the center of a lobule, and opens there. Hominoid (ape and human) placentas are supplied by much larger numbers of arterial convolutions at interlobular areas, with interlobular openings close to anchoring points of villous stems. Venous drainage is at the periphery in Tarsius and interlobular in all other forms. The interlobular intervillous space may have more or less specialized portions emptying into maternal veins. Circulation in the intervillous space must be directed from the center toward the periphery of the lobule in Tarsiidae and Ceboidea. In Cercopithecoidea and Hominoidea the path of maternal blood issuing from arteries is not known. It is suggested that arterial blood irrigates first the periphery, and that this is the cause of dense proliferation of villi there.

Studies on the Pathology of Dicrocoeliasis and Fascioliasis in the Goat I. The Histopathology of the Liver and Bile Ducts

Comparative studies were made on the histopathology of the liver and bile ducts in dicrocoeliasis and fascioliasis of the goat. Investigations revealed certain similarities in the nature of the pathological phenomena produced by D. dendriticum and F. hepatica. However, a feature peculiar to fascioliasis was the migratory tracks of immature flukes in the liver parenchyma. Further, the lesions produced by fascioliasis were distinctly more pronounced than those present in dicrocoeliasis. In both parasitic diseases the bile-duct walls showed glandular hyperplasia, increased frequency of goblet cells and globule leucocytes, and extensive fibrosis in the outer layers. The desquamation produced by Dicrocoelium remained superficial whereas Fasciola was capable of causing deep erosions in the walls of the main bile ducts. The bile-duct walls did not become calcified. Increased fibrosis was present in the interlobular areas, too, but only fascioliasis produced extensive disorganisation of the hepatic architecture, due to the scars originating from repaired migratory tracks. The liver parenchymal cells were degenerated, showed decreased glycogen but were increasingly infiltrated by neutral fats.

Vascular organization of the human placenta.

THE currently accepted theory of maternal blood flow through the intervillous space of the primate placenta1 is that maternal blood entering through basally situated spiral arterioles spurts up towards the chorionic plate under the influence of the vis a tergo of the maternal arterial pressure, spreads laterally and falls back to drain through basal venous openings. Short circuiting from artery to adjacent vein is believed to be avoided purely by virtue of the arterial pressure. This theory based on. cineangiographic evidence takes no account of the structure of the foetal portion of the placenta. The latter consists of numerous lobules or cotyledons of which the principal fifty to sixty are arranged in the form of hollow centred bush-like structures as seen in corrosion casts of the foetal vasculature2,3. Each lobule arises by a main chorionic stem, and is supplied through a major branch of an umbilical artery. Subsequent branches supply an extensive capillary network within the mass of terminal villi which crowd round the central intralobular space. This lobular pattern can be recognized in histological sections in the form of dense masses of villi orientated round cavities4. Interlobular and subchorial areas show greater separation between the villi.

Congenital pulmonary lymphangiectasis.

CONGENITAL pulmonary lymphangiectasis is the name applied by Laurence1to a rare, usually fatal disease, characterized by dilated lymphatic channels in the subpleural and interlobular areas of the lungs of infants. Ekelund et al2recently published a review of the literature and found 26 such cases. The present report deals with a full-term male infant who died in respiratory failure nine hours following birth and demonstrated congenital pulmonary lymphangiectasis at autopsy. This patient differs from those previously reported in that a pneumothorax was present. Report of a Case The patient was a full-term white male infant born by spontaneous vaginal delivery, without maternal anesthesia. It was the second uneventful pregnancy for the 20-year-old mother. The first stage of labor was four hours, the second stage of labor one half hour, and the membranes ruptured spontaneously one hour prior to delivery. The baby received an Apgar 10 on delivery

Mechanisms of Improvement in Bronchopulmonary Disease

The four most common of the chronic bronchopulmonary diseases, asthma, bronchitis, pneumonitis and emphysema, show great similarity in symptoms, physical findings, and x-ray picture. Therapy at the onset is similar in all these conditions. Long term therapy should be planned in consideration of the anatomic and pathologic changes which have occurred and be designed to take advantage of the methods and mechanisms by which improvement may occur. This study was done on 64 patients who demonstrated serious dyspnea, wheezing, cough and obvious loss of respiratory reserve. They were studied by x-ray examination, physical findings, electrocardiogram and pulmonary function testing. Treatment programs were instituted and progress evaluated at regular intervals. Asthma is a disease of allergic origin marked by bronchial obstruction caused by edema of the mucosa, spasm of the bronchi and large amounts of viscous secretion. The lung is not involved. Bronchial infection is an almost constant finding in chronic asthma. Improvement depends upon therapy designed to create and maintain a free airway and equalization of ventilation. Bronchitis demonstrates a clinical picture similar to asthma with, however, permanent pathology in the bronchial tree, more resistant to improvement and more likely to recur. Improvement depends upon elimination of infection, maintenance of a clear airway and adequate ventilation to aid in the drainage of bronchial secretion. Since the pathology is permanent, therapy must be continued after all the symptoms have disappeared. Pneumonitis is an inflammatory process involving the interalveolar septa and the interlobular areas of the lung. As a clinical entity it is associated with bronchial infection, frequently chronic bronchitis. Improvement depends upon treatment of the chronic bronchitis and an attempt to improve the expansion of the lung to yield more adequate ventilation. This improvement is limited by the degree of irreversible fibrosis. The pathology is permanent and all treatments must be continued indefinitely. Emphysema is a disease with diffuse bronchiolar obstruction associated with destruction of alveolar components. It is a diffuse disease with so complex a clinical picture that the therapy must be complex likewise. No one mode of treatment is adequate. Both bronchial and pulmonary pathology are permanent and irreversible. Improvement depends upon treatment of complicating bronchial factors, equalization of ventilation as much as is possible and the development of a more efficient type of ventilation correlated with physical activity. In all four types of disease, one mode of therapy was constant: bronchodilatation and maintenance of adequate ventilation. IPPB with a proper bronchodilator was found to meet this need. The bronchodilator must be one that can be continued for long periods of time without undesirable side reactions. Individual treatment and methods of rehabilitation must be determined by the particular pathophysiologic changes in each disease. Cardiac problems are frequently associated with chronic bronchopulmonary disease. These may be arteriosclerotic in origin because of the age of the average patient or cor pulmonale caused by the pulmonary disease. Improvement which occurs in cardiac status is generally due to the increased oxygenation of the blood and therefore of the myocardial muscle as well as to the reduction of pressure in the chest. All therapy must be long term in nature and regulated by the pathophysiologic changes which are occurring in the patient.

Venous stasis in the transition of edematous pancreatitis to necrosis.

CURRENT CONCEPTS emphasize the importance of pancreatic duct obstruction, combined with exocrine hypersecretion, as an important mechanism responsible for the initiation of pancreatic inflammatory disease.¹Duct hypertension is associated with the release of pancreatic enzymes into the interstitial areas of the gland and is manifested clinically by pain, nausea, and vomiting. Recent studies have shown that proteolytic enzymes, introduced into the interstitial tissues, increase the permeability of local pancreatic blood vessels.²Fluid extravasted into the interlobular areas varied from a simple serous type of transudate to a grossly bloody fluid, depending upon the amount of enzyme injected. Earlier studies have confirmed that an incubated mixture of autologous whole blood and trypsin produced severe necrosis when injected into the pancreatic ducts of dogs.³Nemir and his associates were first to describe this phenomenon; they demonstrated the presence of an abnormal hemin pigment in enzyme-digested blood.⁴Our