Reticuloendothelial Cells Of Liver Research Articles

Excessive Erythrocytosis Is Not Associated With Altered Iron Homeostasis in Men From the World's Highest City.

Excessive Erythrocytosis Is Not Associated With Altered Iron Homeostasis in Men From the World's Highest City.

Amphiphilic dextran/magnetite nanocomposites as magnetic resonance imaging probes

Superparamagnetic iron oxide (SPIO) nanoparticles are effective contrast agents for enhancement of magnetic resonance imaging at the tissue, cellular or even molecular levels. High quality SPIO nanoparticles can be synthesized in the organic phase but need to be transferred into water before any biomedical applications. In this study, amphiphilic poly(e-caprolactone) grafted dextran (Dex-g-PCL) was used as carriers for particle encapsulation and stabilization in the aqueous phase. Multiple SPIO nanoparticles were self-assembled together with the help of Dex-g-PCL during phase transfer from chloroform to water, and diameters of Dex-g-PCL/SPIO nanocomposites were (64 ± 22) nm through dynamic light scattering measurement. These nanocomposites were superparamagnetic at 300 K with saturated magnetization of 88 emu/g Fe. In the magnetic field of 1.5 T, Dex-g-PCL/SPIO nanocomposites had a T2 relaxivity of 363 Fe mL·mol−1·s−1. This unique nanocomposite brought significant mouse liver contrast with signal intensity changes of −60% at 5 min after intravenous administration. However, uptake of Dex-g-PCL/SPIO nanocomposites in liver reticuloendothelial cells (Kupffer cells) did not immediately happen at shorter time points (〈4 h) as verified by histology studies, and it was evident that more iron staining would be located in Kupffer cells 24 h after contrast agent administration. After 24 h and 10 d, the signal intensities (SI) gradually recovered, and SI changes were −44% and −31%, respectively. From our observation, the time window for enhanced-MRI could last at least 12 days and totally recovered after 16 days. This novel sensitive MRI contrast agent may find potential applications in discovering small liver lesions such as early tumor diagnosis.

Multiple Hepatic Clearance Receptors Facilitate Elimination of Secretory Mucins that Can Enter the Bloodstream in Pathological States and Generate Platelet-Rich Microthrombi.

Epithelial cells that line hollow organs typically secrete mucins and their proteolytic fragments vectorially, into the lumen of the organ. Fragments of these large, heterogeneously O-glycosylated molecules can enter the blood stream during injury, inflammation or malignancy involving such organs. We have previously shown that intravenous injection of human carcinoma mucin fragments into mice triggered a “Trousseau”-like syndrome consisting of extensive formation of platelet- and leukocyte-rich microthrombi that were thrombin-independent, but L-and P-selectin-dependent and heparin-sensitive (Wahrenbrock et al., 2003, J Clin Invest, 112, 853–62). Thus, we hypothesized that mechanisms should exist to clear such mucin fragments when they enter the bloodstream in various pathological states. Indeed, intravenously injected radiolabeled mucin fragments had a circulating half-life of ~1 minute in mice, due to rapid and specific clearance by liver reticuloendothelial cells. Competition of uptake by inhibitors of known glycan-recognizing hepatic clearance receptors showed that several overlapping and non-overlapping systems work in concert to remove mucin fragments from the circulation. The systems involved include the hepatic asialoglycoprotein receptor, the macrophage Gal/GalNAc and Mannose receptors, and the endothelial S4GGnM and hyaluronan receptors. Studies of genetically deficient mice, and competition studies amongst various differently glycosylated mucins confirm this result. Thus, multiple hepatic clearance receptors collaborate to varying degrees to ensure elimination of the many polydisperse and differentially glycosylated forms of secretory mucins that might enter the blood circulation from various hollow organs, thus limiting their ability to cause pathology involving disseminated platelet and leukocyte aggregation. This process could also potentially modulate circulating levels of mucin epitopes that are sometimes used as diagnostic criteria in cancer (e.g., CA125, CA19-9 etc.). Furthermore, it can explain why mucin-type clustered O-glycosylation is very uncommon on circulating plasma proteins.

Deletion of Murine Smn Exon 7 Directed to Liver Leads to Severe Defect of Liver Development Associated with Iron Overload

Spinal muscular atrophy (SMA) is characterized by degeneration of lower motor neurons caused by mutations of the survival motor neuron 1 gene (SMN1). SMN is involved in various processes including the formation of the spliceosome, pre-mRNA splicing and transcription. To know whether SMN has an essential role in all mammalian cell types or an as yet unknown specific function in the neuromuscular system, deletion of murine Smn exon 7, the most frequent mutation found among SMA patients, has been restricted to liver. Homozygous mutation results in severe impairment of liver development associated with iron overload and lack of regeneration leading to dramatic liver atrophy and late embryonic lethality of mutant mice. These data strongly suggest an ubiquitous and essential role of full-length SMN protein in various mammalian cell types. In SMA patients, the residual amount of SMN allows normal function of various organs except motor neurons. However, data from mouse and human suggest that other tissues might be involved in severe form of SMA or during prolonged disease course which reinforce the need of therapeutic approaches targeted to all tissues. In addition, liver function of patients should be carefully investigated and followed up before and during therapeutic trials.

4. An in vitro study to compare 99mTc stannous colloids and 99mTc-HMPAO for labelling human leukocytes

Aim of the present study was to compare in vitro the labelling efficiency (LE) and cell viability (TBE) of autologous leukocytes labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO, and to evaluate the quantity and quality of spontaneously released (99m)Tc (SR) from labelled cells at several time points after labelling. A total of 14 patients with different diseases and 18 normal subjects were included in this study. A blood sample was collected from each patient; purified autologous leukocytes were divided into 2 samples and labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO. LE was evaluated at the end of labelling and TBE and SR were evaluated at 10 min and 1 h, 2 h and 4 h after labelling. LE of (99m)Tc-SnF(2)-WBC was higher than (99m)Tc-HMPAO-WBC (61.2+/-18.7% and 43.3+/-11.3; p<0.0001) and we found an inverse correlation between blood glucose and labelling efficiency for both methods (p=0.02). Minimal differences were also observed between 2 methods after 10 min and 1 h, as far as the cell viability is concerned. The percentage of radioactivity spontaneously released from (99m)Tc-SnF(2)-WBC was significantly higher compared to (99m)Tc-HMPAO-WBC at each time point. Radioactivity released from labelled cells was predominantly (99m)Tc-SnF(2) and (99m)Tc-HMPAO with few free (99m)Tc (<20%). Both radiopharmaceuticals are not toxic for WBC. Labelling with (99m)Tc-SnF(2) give a higher LE than with (99m)Tc-HMPAO; however, radiolabelled colloids are more released from labelled cells over a period of 4 h. While (99m)Tc-HMPAO is physiological excreted into gastrointestinal tract, (99m)Tc-SnF(2) can be re-uptaken in vivo by reticulo-endothelial cells of liver and spleen. These findings suggest that (99m)Tc-SnF(2)-WBC might be better than (99m)Tc-HMPAO-WBC for studying inflammatory bowel diseases.

Extravascular haemolytic anaemia in chicks infected with highly pathogenic Marek's disease viruses

Chicks were infected at 1 day of age with highly pathogenic AC-1 or RB-1B isolates of Marek's disease virus and 14 to 36 days post-exposure they were bled for haematocrits and euthanized. At necropsy, specimens were collected for light and electron microscopy. Both viruses caused significant reductions in packed cell volume (P<0.01). Hyperplasia of reticuloendothelial (RE) cells in the liver was a common finding in chicks that were ill from infection with AC-1 or RB-1B viruses. Erythrophagocytosis by sinusoidal macrophages was common and some of these cells contained an overload of haemosiderin. RE cells in the spleen were also active in destruction of erythrocytes. In chicks that were severely affected by AC-1 virus(s) there were often groups of RE cells in liver that had undergone lytic necrosis. Some of these foci appeared to have been replaced by proliferative lesions that ranged from being lymphogranulomatous to neoplastic. Tumour development was more apparent with RB-1B than with AC-1 and the multiple tiny lymphomas observed in RB-1B infected livers appeared to have developed from sinusoidal mononuclear cells. Ultrastructurally, Kupffer cells often contained stacks of electron light cisternal tubules that were densely packed with parallel fibrils. There were also groups of short electron opaque cisternal tubules that sometimes contained ghosts of fibrils packed in parallel. These organelles gave positive reactions for catalase and peroxidase and might have been peroxisomes that developed from the cisternal system due to the overload with iron. It was concluded that extravascular haemolytic anaemia resulted from erythrophagocytosis by hyperplastic RE cells.

ドラッグデリバリーの空間的・時間的制御 生物の分子局在化機構と酵素分子設計

Reactive oxygen species have been postulated to underlie the pathogenesis of various diseases. Since these species rapidly react with various molecules, they should be scavenged appropriately at their site of generation. Superoxide dismutase (SOD) and related antioxidants have been expected to protect tissues from oxygen toxicity. However, because of their unfavorable pharmacokinetic properties, they often failed to inhibit oxidative tissue injury. In case of Cu/Zn-SOD, it disappeared from the circulation with a half-life of 5 min and underwent urinary excretion. Hence, intravenously administered SOD failes to dismutate superoxide radicals in vivo. The present work describes the chemical and genetic methods for targeting SOD to the site of generation and/or pathologic action of superoxide radical. Some SOD derivatives (SM-SOD, FA-SOD) reversibly bind to endogenous albumin thereby remain in the circulation with a half-life of 6 hr. Other derivatives (GSL-SOD, MAN-SOD, AH-SOD) selectively accumulate in hepatocytes, reticuloendothelial cells of liver, spleen and other tissues and renal proximal tubule cells, respectively. The fusion SOD (HB-SOD) preferentially binds to vascular endothelial cells thereby dismutates superoxide radicals in and around vascular walls. Pathophysiological role of superoxide and related free radicals, such as nitric oxide, were studied using these site-directed SODs.

Suppression of humoral immunity in chickens with carrageenans

Carrageenans (CGN), sulphated polygalactans, have been reported to be cytotoxic for macrophages in vitro. On this basis, the effect of the 3 major CGN types on humoral immune responses in chickens was investigated. Carrageenan had no effect on body and lymphoid organ weights. Histologically, CGN produced a significant proliferation of reticuloendothelial cells in liver and spleen, but no changes were observed in lymphocyte populations of the bursa of Fabricius, thymus, or spleen. Intracoelomic pretreatment with high doses of CGN induced a marked suppression of primary responses to sheep red blood cells (SRBC) given by the same route. However, if SRBC were injected intravenously into chickens already treated intracoelomically with CGN, no evidence of suppression was demonstrated. Antibody responses to Brucella abortus (BA), a T-independent antigen, were not affected by intracoelomic treatment with CGN. Intravenous pretreatment with CGN did not alter antibody responses to SRBC and BA given by the same route.

Turnover and tissue uptake of rabbit ferritin from rabbit plasma

Using a two-site immunoradiometric assay for rabbit liver ferritin normal NZW rabbits were found to have very low plasma ferritin concentrations (less than 4 micrograms/l). Purified preparations of rabbit liver and kidney ferritin were labelled with 125I and injected into rabbits. Clearance from plasma was extremely rapid with an initial half-life of 1-2 min as measured by immunoprecipitation of labelled ferritin. The rate of clearance was unaffected by the labelling procedure and by the method of ferritin purification. Autoradiography and organ uptake studies showed that 125I-rabbit liver ferritin was removed mainly by liver reticuloendothelial cells, although on a weight basis, spleen had the greatest radioactivity. These studies indicate that rabbit ferritin released into the circulation is promptly cleared by the RES.

Infection of young adult mice with dengue virus type 2

Young adult female mice, five to six weeks old, were injected intraperitoneally with 2·5 × 10 6·3 LD 50 of dengue-2 virus, New Guinea C strain. The mice were killed on day 1, 2, 3, 4, 5, 6, 7, 10, 14, 21, 28 and 35 respectively. By means of the immunofluorescent antibody technique, viral antigen appeared as irregular granules in the reticuloendothelial cells of liver, lymph nodes and spleen of infected mice on the first day after inoculation and then diminished. From the fifth to sixth day of infection dengue antigen appeared again as homogeneous staining in the cytoplasm of single or groups of mononuclear cells in the lymphatic sinuses only. Later, by the third week of infection, dengue antigen could be seen in the mononuclear cells located in the marginal zone of lymphoid follicle of the spleen, the pattern of staining changing to bright spherical granules. At the same time, the deposition of immune complexes (composed of dengue antigen, mouse gamma and β1C globulin) could be seen in the renal glomeruli of infected mice. Serum antibody to dengue virus was found at low levels, being maximal on the 14th day after infection. Dengue virus was not isolated from the sera or from the infected organs. Granulomatous inflammation developed in lymph nodes and liver of mice infected with dengue virus and in mice inoculated with normal mouse brain suspension. Proliferative glomerular lesion was observed on day 14 after inoculation without definite abnormal urine findings.

The influence of increased hepatic sequestration after splenectomy on the survival and osmotic fragility of red cells in rats, with reference to protein levels in diets.

The sequestration of erythrocytes in rats was studied using an isologous 51Cr-labeled population of either normal or N-ethyl-maleimide (NEM) treated red cells. The spleen sequestered the damaged red cells selectively, while the liver compensated and overshot the sequestration for spleen after splenectomy. The sequestering response in liver increased gradually reaching a maximum level around 8 weeks after splenectomy and then declining toward the control level. These compensatory responses in liver were not observed in rats fed a low-protein diet, which indicated that the proliferative response imposed on liver by an extra work after splenectomy was not stimulated in the rats fed a low-protein diet. Splenectomy prolonged erythrocyte survival and reduced the osmotic fragility of normal red cells, but the compensatory increase in sequestration of damaged red cells in liver did not alter the survival and osmotic fragility of normal red cells of the rat. This fact indicates that the increased sequestration of reticuloendothelial cells in liver is basically reparative, and it is impossible to compensate for the absence of the spleen because of an inability to duplicate certain anatomic features peculiary to the spleen.

Neuronale Migrationsstörung bei Cerebro-Hepato-Renalem Syndrom „Zellweger”1

A reports is given on a male infant aged 4 months with negative family history and normal delivery. The clinical features were characteristic cranio-facial changes, limb abnormalities, extreme congenital muscular hypotonia. and psychomotor retardation. Radiology disclosed abnormal punctual calcifications in both patellae and in the squama of the os occipitale. Laboratory findings indicated partial, non-specific aminoaciduria. Necropsy findings showing superficial renal pseudocysts, deposition of iron pigment in the reticuloendothelial cells of liver, so-called early symmetric neuronal migration disorders in the brain with micropolygyria and multiple gray heterotopias in the deep cerebral and cerebellar hemispheres were suggestive for a typical case of ZELLWEGERS cerebro-hepato renal syndrome. The related neuropathological findings are dicussed.

Progress in the beagle studies at the University of Utah.

Abstract Young adult beagles are given single intravenous injections of monomeric 252Cf, 249Cf, 241Am, 239Pu, 228Th, 226Ra, 228Ra or 90Sr in citrate solution to achieve reproducible deposition patterns in tissue. Injected transuranium atoms become attached to transferrin and other substances in blood plasma. The skeleton and liver are the primary sites of deposition, although high local concentrations of californium, berkelium and americium also occur in the thyroid and kidney, and radium also concentrates in the eye. The initial skeletal deposition of monomeric transuranium elements is on bone surfaces. The mean local dose-rate to the soft-tissue layer 0–10 mi from the mineralized bone surfaces of the beagle is about 20 times higher when 239Pu is on bone surfaces than for an equal amount of 239Pu randomly distributed throughout the bone mineral. Thus, the rate of bone-surface remodeling has a very important influence on the skeletal toxicity of the transuranium elements. The initial liver deposition of monomeric transuranium elements is rather uniform and mainly in the hepatic cells. Subsequently, much of the radioactivity shifts into the liver reticulo-endothelial cells that line the sinusoids. At long times after injection, the distribution is very non-uniform, being highest in the portal region and lowest in the regenerative nodules. All, or virtually all, of the life-shortening from medium and low doses has been due to radiation-induced cancer. Bone sarcomas have been the most frequent form of malignancy, but head sinus carcinomas, liver tumors, and eye melanomas have also been induced. On the basis of average skeletal dose, 1 rad from 239Pu is the equivalent of 5–10 rads from 226Ra in the induction of bone sarcomas. This is because in the skeleton a considerable fraction of the 239Pu disintegrations occur on bone surfaces near cells, whereas most of the skeletal disintegrations from 226Ra take place within bone mineral. Plutonium will continue to be our chief interest, not only at low doses, but perhaps at different ages and in different chemical forms. We will continue to study other radionuclides of practical and fundamental importance. Ours is the first experiment in which tumor induction by fission fragments (252Cf) is being determined.

The ultrastructure of the liver reticulo-endothelial cells in diabetics

The following utrastructural modifications were noticed in a group of 28 diabetic and 2 normal individuals: a) a rather patchy endothelial proliferation with b) frequent hypertrophy which occasionally arrives to obliterate the sinusoidal lumen; c) increased number of cytoplasmic organelles and lysosomes, big and irregular nuclei; d) numerous and various in shape pseudopodic cellular prolongations; e) reduced number of pynocytoticcaveolae intracellulares; f) a certain dilatation of the rough ergastoplasmic reticulum. Comparison was made with the changes noticed in the same patient in the peripheric capillaries (biopsies of the calf) and a functional study of the reticuloendothelial system of the liver (nicotinic acid i.v. test) was carried out. The existence of the diabetic microangiopathy in the liver is discussed as part of the known diabetic vascular changes described in the peripheric capillaries and the possibility of micro-ischaemic disturbances in the liver itself is suggested.

Location of sites of 5-hydroxytryptamine storage and metabolism by radioautography.

1. A technique for the radioautographic identification, localization, and study of the turnover of cellular depots of 5-hydroxytryptamine (5-HT) has been evaluated. A light microscopic survey was made of the uptake and turnover of 5-HT, synthesized in vivo from its administered tritium-labelled precursor, 5-hydroxytryptophan (5-HTP).2. 5-HT was taken up rapidly and retained for long periods of time by adrenal medullary chromaffin cells, gastric enterochromaffin cells, blood platelets, thyroid parafollicular cells, beta cells of pancreatic islets, mast cells, and septal cells of the lung. Reticulo-endothelial cells of liver and spleen took up radioactive 5-HT more slowly but also retained it for days.3. Specific uptake, and a rapid turnover of radioactive 5-HT, was found in pancreatic exocrine cells, neurones of the superior cervical ganglion, terminal axons of gastro-intestinal myenteric plexus, carotid body cells, and pinealocytes.4. A supranuclear localization of radioactive 5-HT in renal proximal tubular cells may represent tubular secretion of 5-HT.5. The localization of 5-HT by radioautography generally corresponds to that found by formaldehyde-induced fluorescence. It makes possible the study of 5-HT turnover and is capable of greater resolution than the fluorescence technique. Freeze-drying may also be avoided.

CYTOLOGICAL STUDY OF THE RETICULOENDOTHELIAL SYSTEM FROM THE OPTICAL MICROSCOPIC STANDPOINT.

Reticulo-endothelial cells of liver, spleen, bone marrow, lymph nodes, thymus, subcutaneous connective tissue, omentum, mesentery, adrenal and hypophysis were demonstrated and defined by the classical vital staining technique with lithion carmine. Further, the increase of vitally stained cells and that of vital staining in a single cell by repeated injection of the dye-stuff or carbon particles were demonstrated and discussed, and it was shown clearly by the radio-auto-graphic technique with tritiated thymidine that Kupffer's stellate cells possessed more active mitotic activity than that of the liver cells. Cytochemical stainings adopted for demonstration of functional states of the reticulo-endothelial cells in fresh section cut with a criostat were PAS, Sudan black B, succinic dehydrogenase, labile and stable oxidase, peroxidase, phosphorylase, acid and alkaline phosphatase, esterase and aminopeptidase stain-ings, and it was concluded that esterase and acid phosphatase were mainly localized in the reticulo-endothelial cells and represented their functional states well.

Cell division and phagocytic activity in liver reticulo-endothelial cells.

SummaryRadioautographs of liver sections from mice given tritiated thymidine were used to identify the cells which were preparing for division and colloidal saccharated iron oxide was used to identify the active phagocytic cells. In livers of mice whose reticulo-endothelial system was stimulated by estradiol, it was established that the cells preparing for division and those which had recently divided were actively phagocytic. In livers of mice whose reticulo-endothelial system had been “blockaded” with saccharated iron oxide, it was established that the cells which had phagocytized colloid were able to divide in the process of recovery from “blockade.” No evidence was found for a stem cell which proliferates and differentiates to provide the active phagocytic population.

Histochemical observations on experimental schistosomiasis of mouse.

SummaryAcid phosphatase, five-nucleotidase, ATPase, aminopeptidase, alkaline phosphatase and non-specific esterase activities were demonstrated in the schistosomal ova in the livers of mice experimentally infected with Schistosoma mansoni. In addition, the ovum contained a complex carbohydrate which is probably its main antigenic component. Granulomatous tissue around the ova displayed histochemical reactions characteristic of chronic proliferative inflammation. The reticuloendothelial cells in liver and spleen exhibited high acid phosphatase activity.

LOCALIZATION OF STREPTOCOCCAL ANTIGENS IN TISSUES

A method has been described for the detection of streptococcal antigens in tissues using the indirect immunofluorescent technique. This method has been applied to the histologic distribution in the mouse of M protein of types 1, 5, 12, and 19. Histologic localization of these M proteins was similar, and their rates of disappearance from the tissues were comparable. The major sites of deposition were the endocardium and adjacent subendocardium of the heart, alveolar walls of the lung, glomerular tufts of the kidney, and reticulo-endothelial cells of liver, spleen, lymph nodes, and adrenal gland. M protein was distributed in considerably lesser concentration in capillary endothelium and connective tissue sites in myocardium, kidney, skin, and gastrointestinal tract. Traces were also present in adrenal cortical cells. It was observed only rarely in cell nuclei. After injection of 0.5 mg. M protein fraction, the concentration of antigen diminished to undetectable levels in all organ sites by 4 days, except in the renal glomerulus, where traces were visible at 8 days. In mice injected with streptococcal culture intraperitoneally, M protein was detected at sites of focal abscesses in liver and spleen, and on the serous surfaces of these organs. The histologic distribution of M protein is compared with that described previously for pneumococcal polysaccharide and animal protein. Differences in the extent of distribution and in the characteristics of antigen deposition are pointed out.

Localization of Colloidal Dyes in Animal Tumors

Summary(1) As earlier workers have shown, acid dyes do not localize in tumor cells but in the stroma surrounding the tumor. (2) Further localization takes place within the tumor at each interface of viable and necrotic tissue. (3) The initial localization consists of a diffuse staining of the peripheral stroma and the seminecrotic cells within the tumor between viable and necrotic zones. (4) This diffuse dye is progressively phagocytized, and after 24-48 hours, appears in numerous macrophages at the tumor edge. (5) The dye is so located that if it were replaced by a radioactive substance, theoretically effective radiation of the tumor edge should result. (6) After a single large dose of dye the reticulo-endothelial cells of liver and spleen are rapidly filled with dye droplets. These disappear or diminish substantially after several days. (7) In addition to tumor and reticulo-endothelial systems of liver and spleen, the kidneys take up considerable quantities of dye, as this is the chief channel of excret...