bluuebunny/crossref_metadata_2025 huggingface dataset:
Thymidylate Synthase Expression in Patients with Colorectal Carcinoma Using a Polyclonal Thymidylate Synthase Antibody in Comparison to the TS 106 Monoclonal Antibody
Authors: Van Triest Baukelien , Loftus Barbara M. , Pinedo Herbert M. , Backus Harold H.J. , Schoenmakers Pascale , Telleman Frank , Tadema Thea , Aherne G. Wynne , Van Groeningen Cornelius J. , Zoetmulder Frans A.N. , Taal Babs G. , Johnston Patrick G. , Peters Godefridus J.
Published: April 2011

Colorectal cancer is one of the most common human cancers, for which 5-fluorouracil (5FU) is usually part of the treatment. Thymidylate synthase (TS), the target enzyme for 5FU, can be predictive for the outcome of 5FU-based therapy. TS levels in tumor samples can be determined with radiochemical enzyme assays, RT-PCR, and immunohistochemical staining. We validated TS immunohistochemistry with a polyclonal rabbit anti-human TS antibody using the avidin-biotin method. This antibody can be used on paraffin-embedded, formalin-fixed material using an antigen retrieval method with citrate buffer and microwave treatment. The antibody shows a granular cytosolic staining pattern. The reproducibility in cross-sections from colorectal tumors from 50 patients was 90% and the interobserver variability was acceptable with a kappa of 0.45. On Western blotting it detects purified TS at 36 kD, while in 5FU-treated cells the ternary complex between FdUMP, TS, and 5,10-methylene-tetrahydrofolate is clearly visible at 38 kD, with no other interfering bands. In a separate set of tumors, immunostaining was compared with enzyme levels; Western blots correlated with enzyme levels. Because both this polyclonal antibody and the monoclonal antibody TS-106 are being used for large-scale studies, we also determined whether they could be used interchangeably. No differences were observed. This polyclonal antibody is specific and gives reproducible results. A study on a larger scale is ongoing to determine the role of TS as a predictive parameter in patients with colorectal cancer treated either with postoperative adjuvant 5FU/levamisole or with surgery only.
Expression of Pancreatic Islet MHC Class I, Insulin, and ICA 512 Tyrosine Phosphatase in Low-dose Streptozotocin-induced Diabetes in Mice
Authors: Li Zhanchun , Zhao Lijun , Sandler Stellan , Karlsson F. Anders
Published: April 2011

Activated immune cells contribute to the development of diabetes mellitus in multiple low-dose streptozotocin-treated mice. However, a role in the process for MHC Class I restricted T-cells remains a matter of debate. In this study, we examined by confocal microscopy the pancreatic expression of MHC Class I protein, insulin, and ICA 512 protein tyrosine phosphatase in C57BL/Ks mice given 40 mg/kg bw streptozotocin IP on 5 consecutive days. All animals were hyperglycemic from Day 7 and onwards. A loss of ICA 512 from the central portions of the islets was noted on Day 3. On Day 7, an increase in MHC Class I expression, confined primarily to immune cells in the exocrine pancreas and the periinsular areas, was detected. Later, several MHC class I/glucagon and some MHC class I/insulin double-positive cells were found. The insulitis was maximal on Day 14 and declined thereafter. The induction of MHC Class I expression in endocrine cells, occuring only after the cellular infiltration and when the animals were diabetic, indicates that the immune component of the disease does not depend on MHC Class I-restricted cytotoxic T-cells but rather comprises a non-antigen-specific process.
Expression of Epidermal Growth Factor and Its Receptor in Cirrhotic Liver Disease
Authors: Kömüves László G. , Feren Anna , Jones Albert L. , Fodor Eric
Published: April 2011

Polypeptide growth factors, including epidermal growth factor (EGF), play a central role in regulating hepatocyte growth both in vivo and in primary culture. To characterize EGF gene expression in the pathogenesis of regenerative cirrhotic fibrosis, we employed biotinylated antisense oligonucleotide probes to localize hepatic mRNA transcripts in situ. In control tissue and regenerative hepatic nodules, EGF receptor (EGFR) mRNA transcripts were expressed constitutively. In contrast, oligonucleotide probes targeting the human EGF coding region showed that EGF transcription was extremely low in control liver but was highly elevated and localized to regenerative hepatic nodules and bile duct epithelia of cirrhotic liver. To determine whether EGF mRNA accumulation accompanied a comparable increase in the EGF peptide, we performed immunohistochemistry using an antibody specific for the nonprocessed peptide aminoterminus. We observed that positive localized EGF staining paralleled its mRNA transcript. These results indicate that EGF upregulation is a characteristic of cirrhotic liver disease and suggest that persistent de novo ligand synthesis and its signaling contribute to an autocrine-mediated hepatocyte proliferation within the regenerative nodule.
Analysis of Tissue Chimerism in Nude Mouse Brain and Abdominal Xenograft Models of Human Glioblastoma Multiforme: What Does It Tell Us About the Models and About Glioblastoma Biology and Therapy?
Authors: Antunes Laurent , Angioi-Duprez Karine S. , Bracard Serge R. , Klein-Monhoven Nathalie A. , Le Faou Alain E. , Duprez Adrien M. , Plénat François M.
Published: April 2011

In situ hybridization coupled to immunohistochemistry for antigens of interest allows unequivocal identification of tumor cells from reactive stroma cells and normal adjacent structures in human glioblastoma multiforme grafts transplanted into nude mice. With this methodology, we have explored the development of glioblastoma multiforme solid grafts transplanted into nude mouse brains or flanks. The brain transplants closely resembled the human situation, particularly in relation to differentiation and growth patterns. The morphological features of peritumoral reactive gliosis were similar to those observed in humans. A mouse glial stroma within the main tumor masses was also demonstrated. Kinetic studies showed that the compartment of isolated tumor cells that infiltrated host brains and the reactive gliosis constituted two cycling cell populations. Despite VEGF protein expression by tumor cells and some reactive astrocytes, the abnormally permeable microvascular beds were not hyperplastic. The observation of a non-infiltrative pattern of growth when grafts were established in host flanks demonstrated that the organ-specific environment plays a determining role in the growth and invasive properties of glioblastoma. The phylogenetic distance between man and mouse and the recipient immunoincompetence should not impose serious limitations on the use of this model for studying malignant glioma biology and therapy in vivo.
Luminal Localization of Blood-Brain Barrier Sodium, Potassium Adenosine Triphosphatase Is Dependent on Fixation
Authors: Manoonkitiwongsa Panya S. , Schultz Robert L. , Wareesangtip Wanpen , Whitter Ernest F. , Nava Pedro B. , McMillan Paul J.
Published: April 2011

Cytochemical data in the literature reporting localization of sodium, potassium adenosine triphosphatase (Na+, K+-ATPase) in the blood-brain barrier (BBB) have been contradictory. Whereas some studies showed the enzyme to be located exclusively on the abluminal endothelial plasma membrane, others demonstrated it on both the luminal and abluminal membranes. The influence of fixation on localization of the enzyme was not considered a critical factor, but our preliminary studies showed data to the contrary. We therefore quantitatively investigated the effect of commonly used fixatives on the localization pattern of the enzyme in adult rat cerebral microvessels. Fixation with 1%, 2%, and 4% formaldehyde allowed deposition of reaction product on both the luminal and abluminal plasma membranes. The luminal reaction was reduced with increasing concentration of formaldehyde. Glutaraldehyde at 0.1%, 0.25%, 0.5%, in combination with 2% formaldehyde, drastically inhibited the luminal reaction. The abluminal reaction was not significantly altered in all groups. These results show that luminal localization of BBB Na+, K+-ATPase is strongly dependent on fixation. The lack of luminal localization, as reported in the literature, may have been the result of fixation. The currently accepted abluminal polarity of the enzyme should be viewed with caution.
An Artifactual In Situ Hybridization Signal Associated with Apoptosis in Rat Embryo
Authors: Raatikainen-Ahokas Anne M. , Immonen Tiina M. , Rossi Petri O. , Sainio Kirsi M.H. , Sariola Hannu V.
Published: April 2011

We report an artifactual in situ hybridization (ISH) labeling pattern in embryonic rat tissues. It is caused by a short multiple cloning site-derived sequence incorporated into the RNA probes by in vitro transcription of templates cloned into pBluescript or its descendants. The artifact was seen in tissues in which programmed cell death (apoptosis) takes place during embryogenesis, i.e., in the mesonephric area, developing nervous system, interdigital mesenchyme of the hand plate, and permanent kidney. Labeling of the radioactive ISH with TUNEL verified the co-localization of the artifactual hybridization signal with cells at early stages of apoptosis. Even though the identity of the hybridization target in apoptotic cells remains unknown, it might be highly species-specific, because this artifact was never observed in mouse tissues.
Protease-elicited TUNEL Positivity of Non-apoptotic Fixed Cells
Authors: Gál István , Varga Tamás , Szilágyi Ildikó , Balázs Margit , Schlammadinger József , Szabó Gábor
Published: April 2011

The appearance of free DNA ends in the chromatin is usually considered an indication of advanced apoptosis. Unexpectedly, the nuclei of non-apoptotic cells derived from mouse thymuses could be specifically labeled by terminal transferase after proteinase K treatment of the fixed, cytocentrifuged samples. Artifactual mechanical or contaminating nucleolytic factors have been ruled out as players in the generation of free DNA ends. The phenomenon was detected in both formaldehyde- and ethanol-fixed specimens, in agarose-embedded fixed cells, and in chromatin spreads. By urea-agarose gel electrophoresis, the average single-strand size of the DNA molecules carrying the free ends was found between 50 and 250 kb. We suggest that ss discontinuities preexisting in the fixed normal cells are unmasked by protease treatment eliciting TUNEL (terminal transferasemediated nick end-labeling) positivity.
Posttranslational Regulation of Glucose-6-phosphate Dehydrogenase Activity in Tongue Epithelium
Authors: Biagiotti Enrica , Bosch Klazina S. , Ninfali Paolino , Frederiks Wilma M. , Noorden Cornelis J.F. Van
Published: April 2011

Expression of glucose-6-phosphate dehydrogenase (G6PD) activity is high in tongue epithelium, but its exact function is still unknown. It may be related either to the high proliferation rate of this tissue or to protection against oxidative stress. To elucidate its exact role, we localized quantitatively G6PD activity, protein and mRNA using image analysis in tongue epithelium of rat and rabbit, two species with different diets. Distribution patterns of G6PD activity were largely similar in rat and rabbit but the activities were twofold lower in rabbit. Activity was two to three times higher in upper cell layers of epithelium than in basal cell layers, whereas basal layers, where proliferation takes place, contained twice as much G6PD protein and 40% more mRNA than upper layers. Our findings show that G6PD is synthetized mainly in basal cell layers of tongue epithelium and that it is posttranslationally activated when cells move to upper layers. Therefore, we conclude that the major function of G6PD activity in tongue epithelium is the formation of NADPH for protection against oxidative stress and that diet affects enzyme expression in this tissue.
Epithelial Rests of Malassez Express Immunoreactivity of TrkA and Its Distribution Is Regulated by Sensory Nerve Innervation
Authors: Yamashiro Takashi , Fujiyama Koji , Fukunaga Tomohiro , Wang Yan , Takano-Yamamoto Teruko
Published: April 2011

The periodontal ligament is the connective tissue that fills the space between the tooth and its bony socket. It is abundantly innervated by the sensory and sympathetic nerves. We first investigated the immunoreactivity of TrkA, which is a high-affinity receptor of nerve growth factor (NGF), in the periodontal ligament of rats. Immunoreactivity was observed at the epithelial cells in the cervical and furcation regions of the molars. These epithelial cells, which gather together to form clusters or networks, are known as the epithelial rests of Malassez. Immunoreactivity was not observed in other non-neuronal cells, such as osteoblasts, fibroblasts, odontoblasts, cementoblasts, endothelial cells, and/or osteoclasts. On the basis of these findings, we investigated the possible involvement of sensory nerve innervation in the immunoreactivity of the epithelial cells. Denervation of the inferior alveolar nerve resulted in a marked decrease in the distribution area and size of the clusters of immunoreactive cells compared with those of sham-operated rats. These findings suggest that sensory nerve innervation may have a regulatory role in maintenance of the epithelial rests of Malassez expressing TrkA in the periodontal ligament.
Cellular Localization of Gene Expression for Progranulin
Authors: Daniel Rachael , He Zhiheng , Carmichael K. Paige , Halper Jaroslava , Bateman Andrew
Published: April 2011

Granulins, also called epithelins, are 6-kD peptides with growth modulatory effects on a variety of cells. The granulin/epithelin precursor supports tumorigenesis in appropriate cell models and is the only growth factor able to overcome the cell cycle block that occurs in murine fibroblasts after deletion of a functional IGF-1 receptor. However, little is known of the role of granulin/epithelin gene products in vivo. To understand the physiological role of granulins it is essential to know the cell types and conditions in which it is expressed. We examined granulin/epithelin gene expression in adult rodents by in situ hybridization. The granulin/epithelin precursor is constitutively expressed in a number of epithelia, particularly in the skin, GI tract, and reproductive system. Other epithelia express the gene less strongly. Progranulin is expressed in immune cells in vivo and in specific neurons in the brain, including Purkinje cells, pyramidal cells of the hippocampus, and some cerebral cortical neurons. Little expression was detected in muscle cell, connective tissue, or endothelium. Cumulatively, these results define the basal gene expression of a new growth factor system and suggest that the progranulin/epithelin gene is multifunctional, with important constitutive roles in epithelial homeostasis, reproductive, immunological, and neuronal function.
Morphological and Immunocytochemical Analyses on the Effects of Diet-induced Hypocalcemia on Enamel Maturation in the Rat Incisor
Authors: Nanci A. , Mocetti P. , Sakamoto Y. , Kunikata M. , Lozupone E. , Bonucci E.
Published: April 2011

During the maturation stage of amelogenesis, the loss of matrix proteins combined with an accentuated but regulated influx of calcium and phosphate ions into the enamel layer results in the “hardest” tissue of the body. The aim of the present investigation was to examine the effects of chronic hypocalcemia on the maturation of enamel. Twenty-one-day old male Wistar rats were given a calcium-free diet and deionized water for 28 days, while control animals received a normal chow. The rats were perfused with aldehyde and the mandibular incisors were processed for histochemical and ultrastructural analyses and for postembedding colloidal gold immunolabeling with antibodies to amelogenin, ameloblastin, and albumin. The maturation stage enamel organ in hypocalcemic rats exhibited areas with an apparent increase in cell number and the presence of cyst-like structures. In both cases the cells expressed signals for ameloblastin and amelogenin. The content of the cysts was periodic acid–Schiff- and periodic acid–silver nitrate–methanamine-positive and immunolabeled for amelogenin, ameloblastin, and albumin. Masses of a similar material were also found at the enamel surface in depressions of the amelo-blast layer. In addition, there were accumulations of glycoproteinaceous matrix at the interface between ameloblasts and enamel. In decalcified specimens, the superficial portion of the enamel matrix sometimes exhibited the presence of tubular crystal “ghosts.” The basal lamina, normally separating ameloblasts and enamel during the maturation stage, was missing in some areas. Enamel crystals extended within membrane invaginations at the apical surface of ameloblasts in these areas. Immunolabeling for amelogenin, ameloblastin, and albumin over enamel was variable and showed a heterogeneous distribution. In contrast, enamel in control rats exhibited a homogeneous labeling for amelogenin, a concentration of ameloblastin at the surface, and weak reactivity for albumin. These results suggest that diet-induced chronic hypocalcemia interferes with both cellular and extracellular events during enamel maturation. (J Histochem Cytochem 48:1043–1057, 2000)
COS Cells Expression Cloning of Tyrosine-phosphorylated Proteins by Immunocytochemistry
Authors: Bianchi Cesario , Sellke Frank W.
Published: April 2011

Tyrosine phosphorylation is an important post-translational modification of proteins, essential in many aspects of the cell economy, particularly in signal transduction pathways. Despite the importance of protein tyrosine phosphorylation, the approaches available for molecular cloning remain limited. We have developed a COS cell-based eukaryotic expression cloning procedure for phosphotyrosine-containing proteins by immunocytochemistry of cell monolayers. The approach takes advantage of the low basal levels of tyrosine phosphorylated, robust transient expression, availability of specific antibodies against tyrosine-phosphorylated residues, and rescue of episomal DNA after immunocytochemistry. The technique is validated by cloning the rat proto-oncogene c-fgr in its tyrosine-phosphorylated form out of a rat kidney cDNA library containing over 106 primary recombinants. This technique set the grounds for expression cloning of tyrosine-phosphorylated proteins in eukaryotic cells, and it is anticipated that further modifications and refinements will allow the identification of protein tyrosine phosphatase substrates. (J Histochem Cytochem 48:1097–1101, 2000)
Immunohistochemical Localization of Protein Gene Product 9.5, Ubiquitin, and Neuropeptide Y Immunoreactivities in Epithelial and Neuroendocrine Cells from Normal and Hyperplastic Human Prostate
Authors: Martìn Rocáo , Fraile Benito , Peinado François , Arenas Maráa I. , Elices Margarita , Alonso Lucáa , Paniagua Ricardo , Martìn José J. , Santamaráa Luis
Published: April 2011

This study was designed to investigate (a) the presence of protein gene product 9.5 (PGP 9.5), ubiquitin, and neuropeptide Y (NPY) in the neuroendocrine and secretory epithelium of the human normal prostate and its secretions, and (b) the changes in immunoreactivity to these proteins in men with benign prostatic hyperplasia. Western blotting and light microscopic immunohistochemistry techniques were used and the numerical density of immunoreactive neuroendocrine cells, and the volume fractions of immunostained secretory epithelium were evaluated. Western blotting revealed the presence of the three antigens in both tissue homogenates and prostate secretion. Some neuroendocrine cells immunoreacted to PGP 9.5 and NPY in all the prostate regions of control specimens. Ubiquitin immunoreactivity was detected in the nuclei from both basal cells and secretory epithelial cells. The cytoplasm of the secretory cells and the glandular lumen also showed immunostaining for the three proteins. The numerical densities of both PGP 9.5 and NPY neuroendocrine cells were lower in hyperplasia than in controls. No differences in the volume fraction occupied by epithelial immunostaining to both proteins was found between hyperplastic and control prostates. We concluded that (a) PGP 9.5 and NPY, but not ubiquitin, are common antigens in both neuroendocrine and secretory prostate cells, (b) the three immunoreactive proteins contribute to the prostate secretions, and (c) the secretion of ubiquitin is markedly diminished in the hyperplastic epithelium. (J Histochem Cytochem 48:1121–1130, 2000)
Subcellular Localization of Leptin in Non-tumorous and Adenomatous Human Pituitaries: An Immuno-ultrastructural Study
Authors: Vidal Sergio , Cohen Sandra M. , Horvath Eva , Kovacs Kalman , Scheithauer Bernd W. , Burguera Bartolome G. , Lloyd Ricardo V.
Published: April 2011

Leptin is a key mediator in the maintenance of neuroendocrine homeostasis. Recently, leptin and leptin receptor expression were demonstrated in non-tumorous and adenomatous human pituitaries. This study was performed to determine the subcellular localization of leptin in human adenohypophyses ( n = 3) and in various types of pituitary adenoma ( n = 16). Immunoelectron microscopy showed leptin immunolabeling in most hormone-producing cells of the human non-tumorous adenohypophysis, but not in stellate cells. Labeling was noted over secretory granules. Immunocytochemistry using double labeling revealed leptin expression in GH-, ACTH-, TSH-, and FSH/LH-containing cells but not in PRL cells. The percentage of immunopositive cells and the intensity of immunostaining varied considerably among the various cell types. Immunoelectron microscopy with double gold labeling showed co-localization of leptin and adenohypophysial hormones in the same secretory granules. Among pituitary tumors, leptin immunolabeling was evident only in corticotroph adenomas. Compared to non-tumorous corticotrophs, leptin immunoexpression was less abundant in corticotroph adenomas. The presence of leptin and adenohypophysial hormones in the same secretory granules suggests that leptin is secreted concomitantly with various adenohypophysial hormones and that its release is under the control of hypothalamic stimulating and inhibiting hormones. (J Histochem Cytochem 48:1147–1152, 2000)
Dual Fluorescent In Situ Hybridization and Immunohistochemical Detection with Tyramide Signal Amplification
Authors: Zaidi Aliya U. , Enomoto Hideki , Milbrandt Jeffrey , Roth Kevin A.
Published: April 2011

To understand the biological relationships among various molecules, it is necessary to define the cellular expression patterns of multiple genes and gene products. Relatively simple methods for performing multi-label immunohistochemical detection are available. However, there is a paucity of techniques for dual immunohistochemical (IHC) and mRNA in situ hybridization (ISH) detection. The recent development of improved non-radioactive detection systems and simplified ISH protocols has prompted us to develop a tyramide signal amplification method for sequential multi-label fluorescent ISH and IHC detection in either frozen or paraffin-embedded tissue sections. We used this method to examine the relationship between glial cell line-derived neurotrophic factor receptor α2 (GFRα2) mRNA expression and IHC localization of its co-receptor Ret in the trigeminal ganglion of postnatal Day 0 mice. We found that approximately 70% of Ret-immunoreactive neurons possessed GFRα2 mRNA and virtually all GFRα2-expressing neurons contained Ret-immunoreactive protein. Finally, we used paraformaldehyde-fixed, paraffin-embedded sections and a monoclonal antibody against neuron-specific nuclear antigen (NeuN) to demonstrate the neuronal specificity of GFRα2 mRNA expression in adult mouse brain. This multi-labeling technique should be applicable to a wide variety of tissues, antibodies, and probes, providing a relatively rapid and simple means to compare mRNA and protein localization.
Overexpression of the reg Gene In Non-obese Diabetic Mouse Pancreas During Active Diabetogenesis Is Restricted to Exocrine Tissue
Authors: Sanchez Didier , Baeza Nathalie , Blouin Richard , Devaux Christiane , Grondin Gilles , Mabrouk Kamel , Guy–Crotte Odette , Figarella Catherine
Published: April 2011

We demonstrated pancreatic reg gene overexpression in non-obese diabetic (NOD) mice during active diabetogenesis. The aim of this study was to determine in which part of the pancreas (endocrine and/or exocrine) the gene(s) and the protein(s) were expressed and if their localization changed with progression of the disease. In situ hybridization analysis and immunocytochemical studies were carried out on pancreas of female and male NOD mice. Both develop insulitis but diabetes develops only in females and in males only when treated by cyclophosphamide. Our results show that whatever the age, sex, and presence of insulitis and/or diabetes, the expression of reg mRNAs and of the corresponding protein(s) was restricted to exocrine tissue. Moreover, reg remains localized in acinar cells in the two opposite situations of (a) cyclophosphamide-treated males in a prediabetic stage presenting a high level of both insulin and reg mRNAs, and (b) the overtly diabetic females with no insulin but a high level of reg mRNA. These findings suggest that overexpression of the reg gene(s) might represent a defense of the acinar cell against pancreatic aggression.
Comparative Localization of Cathepsin B Protein and Activity in Colorectal Cancer
Authors: Hazen Lonny G. M. , Bleeker Fonnet E. , Lauritzen Bjarne , Bahns Sieglinde , Song Jiying , Jonker Ard , Driel Bernard E. M. Van , Lyon Hans , Hansen Ulla , Köhler Angela , Noorden Cornelis J. F. Van
Published: April 2011

Cathepsin B is a lysosomal cysteine proteinase that may participate in cancer progression. We compared localization of its protein and activity during progression of human colorectal cancer. In adenomas and carcinomas, protein expression and, particularly, activity were elevated compared with those in normal colorectal mucosa. In normal mucosa, cathepsin B protein expression was moderate in stroma and variable in epithelium, whereas activity was mainly present in distinct areas of stroma directly underneath the surface of the colon and in epithelium at the surface of the colon. Stroma in adenomas and carcinomas contained moderate to high protein levels but little activity except for areas of angiogenesis, inflammation, and necrosis, in which activity was high. In adenomas and the majority of well-differentiated carcinomas and moderately differentiated carcinomas, cathepsin B protein and activity were found in granular form in the epithelium, close to the basement membrane. Protein and activity levels were low and diffusely distributed in cancer cells in the remainder of the well-differentiated and moderately differentiated carcinomas and in all poorly differentiated carcinomas. Invasive fronts in most cancers contained moderate protein levels but high activity. We conclude that (a) activity localization is essential to understand the role of cathepsin B in cancer progression, and (b) cathepsin B activity in human colon is associated with invasion of cancer cells, endothelial cells, and inflammatory cells, and in cell death, both apoptotic and necrotic.
Bone Morphogenetic Protein (BMP) Localization in Developing Human and Rat Growth Plate, Metaphysis, Epiphysis, and Articular Cartilage
Authors: Anderson H. Clarke , Hodges Peter T. , Aguilera Ximena M. , Missana Lilliana , Moylan Paul E.
Published: April 2011

We assessed the distribution and relative staining intensity of bone morphogenetic protein (BMP)-1–7 by immunohistochemistry in tibial growth plates, epiphyses, metaphyses, and articular cartilage in one 21-week and one 22-week human fetus and in five 10-week-old Sprague–Dawley rats. In the rats, articular cartilage was also examined. BMP proteins were mostly cytoplasmic, with negligible matrix staining. Highest BMP levels were seen in (a) hypertrophic and calcifying zone chondrocytes of growth plate (BMP-1–7), (b) osteoblasts and/or osteoprogenitor fibroblasts and vascular cells of the metaphyseal cortex and medulla (BMP-1–6), (c) osteoclasts of the metaphysis and epiphysis (BMP-1,-4,-5, and −6), and (d) mid to deep zone articular chondrocytes of weanling rats (BMP-1–7). BMP staining in osteoclasts, an unexpected finding, was consistently strong with BMP-4, −5, and −6 but was variable and dependent on osteoclast location with BMP-2,-3, and −7. BMP-1–7 were moderately to intensely stained in vascular canals of human fetal epiphyseal cartilage by endothelial cells and pericytes. BMP-1,-3,-5,-6, and −7 were localized in hypertrophic chondrocytes adjacent to cartilage canals. We conclude that BMP expression is associated with maturing chondrocytes of growth plate and articular cartilage, and may play a role in chondrocyte differentiation and/or apoptosis. BMP appears to be expressed by osteoclasts and might be involved in the intercellular “cross-talk” between osteoclasts and neighboring osteoprogenitor cells at sites of bone remodeling.
Tissue Distribution of the Lipocalin Alpha-1 Microglobulin in the Developing Human Fetus
Authors: Lögdberg Lennart E. , Åkerström Bo , Badve Sunil
Published: April 2011

Alpha-1 microglobulin (α1m), a lipocalin, is an evolutionarily conserved immunomodulatory plasma protein. In all species studied, α1m is synthesized by hepatocytes and catabolized in the renal proximal tubular cells. α1m deficiency has not been reported in any species, suggesting that its absence is lethal and indicating an important physiological role for this protein To clarify its functional role, tissue distribution studies are crucial. Such studies in humans have been restricted largely to adult fresh/frozen tissue. Formalin-fixed, paraffin-embedded multi-organ block tissue from aborted fetuses (gestational age range 7–22 weeks) was immunohistochemically examined for α1m reactivity. Moderate to strong reactivity was seen at all ages in hepatocytes, renal proximal tubule cells, and a subset of pancreatic islet cells. Muscle (cardiac, skeletal, or smooth), adrenal cortex, a scattered subset of intestinal mucosal cells, tips of small intestinal villi, and Leydig cells showed weaker and/or variable levels of reactivity. Connective tissue stained with variable location and intensity. The following cells/sites were consistently negative: thymus, spleen, hematopoietic cells, lung parenchyma, glomeruli, exocrine pancreas, epidermis, cartilage/bone, ovary, seminiferous tubules, epididymis, thyroid, and parathyroid. The results underscore the dominant role of liver and kidney in fetal α1m metabolism and provide a framework for understanding the functional role of this immunoregulatory protein.
Fluorescence In Situ Hybridization of Scarce Leptin Receptor mRNA using the Enzyme-Labeled Fluorescent Substrate Method and Tyramide Signal Amplification
Authors: Breininger John F. , Baskin Denis G.
Published: April 2011

To increase the sensitivity of fluorescence in situ hybridization (FISH) for detection of low-abundance mRNAs, we performed FISH on cryostat sections of rat hypothalamus with biotin-labeled riboprobes to leptin receptor (ObRb) and amplified the signal by combining tyramide signal amplification (TSA) and Enzyme-Labeled Fluorescent alkaline phosphatase substrate (ELF) methods. First, TSA amplification was done with biotinylated tyramide. Second, streptavidin–alkaline phosphatase was followed by the ELF substrate, producing a bright green fluorescent reaction product. FISH signal for ObRb was undetectable when TSA or ELF methods were used alone, but intense ELF FISH signal was visible in hypothalamic neurons when the ELF protocol was preceded by TSA. The TSA–ELF was combined with FISH for pro-opiomelanocortin (POMC) and neuropeptide Y (NPY) mRNAs by hybridizing brain sections in a cocktail containing digoxigenin-labeled riboprobes to NPY or POMC mRNA and biotin-labeled riboprobes to ObRb mRNA. Dioxigenin-labeled NPY or POMC mRNA hybrids were subsequently detected first with IgG–Cy3. Then biotin-labeled leptin receptor hybrids were detected with the TSA–ELF method. Combining the ELF and TSA amplification techniques enabled FISH detection of scarce leptin receptor mRNAs and permitted the identification of leptin receptor mRNA in cells that also express NPY and POMC gene products.
Expression of the Membrane-associated Carbonic Anhydrase Isozyme XII in the Human Kidney and Renal Tumors
Authors: Parkkila Seppo , Parkkila Anna-Kaisa , Saarnio Juha , Kivelä Jyrki , Karttunen Tuomo J. , Kaunisto Kari , Waheed Abdul , Sly William S. , Türeci Özlem , Virtanen Ismo , Rajaniemi Hannu
Published: April 2011

Carbonic anhydrase isozyme XII (CA XII) is a novel membrane-associated protein with a potential role in von Hippel–Lindau carcinogenesis. Although Northern blotting has revealed positive signal for CA XII in normal human kidney, this is the first study to demonstrate its cellular and subcellular localization along the human nephron and collecting duct. Immunohistochemistry with a polyclonal antibody (PAb) raised against truncated CA XII revealed distinct staining in the basolateral plasma membrane of the epithelial cells in the thick ascending limb of Henle and distal convoluted tubules, and in the principal cells of the collecting ducts. A weak basolateral signal was also detected in the epithelium of the proximal convoluted tubules. In addition to the normal kidney specimens, this immunohistochemical study included 31 renal tumors. CA XII showed moderate or strong plasma membrane-associated expression in most oncocytomas and clear-cell carcinomas. The segmental, cellular, and subcellular distribution of CA XII along the human nephron and collecting duct suggests that it may be one of the key enzymes involved in normal renal physiology, particularly in the regulation of water homeostasis. High expression of CA XII in some renal carcinomas may contribute to its role in von Hippel–Lindau carcinogenesis.
Localization of Xenin-immunoreactive Cells in the Duodenal Mucosa of Humans and Various Mammals
Authors: Anlauf Martin , Weihe Eberhard , Hartschuh Wolfgang , Hamscher Gerd , Feurle Gerhard E.
Published: April 2011

Xenin is a 25-amino-acid peptide extractable from mammalian tissue. This peptide is biologically active. It stimulates exocrine pancreatic secretion and intestinal motility and inhibits gastric secretion of acid and food intake. Xenin circulates in the human plasma after meals. In this study, the cellular origin of xenin in the gastro-entero-pancreatic system of humans, Rhesus monkeys, and dogs was investigated by immunohistochemistry and immunoelectron microscopy. Sequence-specific antibodies against xenin detected specific endocrine cells in the duodenal and jejunal mucosa of all three species. These xenin-immunoreactive cells were distinct from enterochromaffin, somatostatin, motilin, cholecystokinin, neurotensin, and secretin cells, and comprised 8.8% of the chromogranin A-positive cells in the dog duodenum and 4.6% of the chromogranin A-positive cells in human duodenum. In all three species, co-localization of xenin was found with a subpopulation of gastric inhibitory polypeptide (GIP)-immunoreactive cells. Immunoelectron microscopy in the canine duodenal mucosa demonstrated accumulation of gold particles in round, homogeneous, and osmiophilic secretory granules with a closely adhering membrane of 187 ± 19 nm diameter (mean ± SEM). This cell type was found to be identical to the previously described canine GIP cell. Immunocytochemical expression of the peptide xenin in a subpopulation of chromogranin A-positive cells as well as the localization of xenin immunoreactivity in ultrastructurally characterized secretory granules permitted the identification of a novel endocrine cell type as the cellular source of circulating xenin.
Distinct Aggregation of β- and γ-Chains of the High-affinity IgE Receptor on Cross-Linking
Authors: Asai Koichi , Fujimoto Kazushi , Harazaki Masashi , Kusunoki Takashi , Korematsu Seigo , Ide Chizuka , Ra Chisei , Hosoi Susumu
Published: April 2011

The high-affinity IgE receptor (Fc∊RI) on mast cells and basophils consists of a ligand-binding α-chain and two kinds of signaling chains, a β-chain and disulfide-linked homodimeric γ-chains. Crosslinking by multivalent antigen results in the aggregation of the bound IgE/α-chain complexes at the cell surface, triggering cell activation, and subsequent internalization through coated pits. However, the precise topographical alterations of the signaling β- and γ-chains during stimulation remain unclarified despite their importance in ligand binding/signaling coupling. Here we describe the dynamics of Fc∊RI subunit distribution in rat basophilic leukemia cells during stimulation as revealed by immunofluorescence and immunogold electron microscopy. Immunolocalization of β- and γ-chains was homogeneously distributed on the cell surfaces before stimulation, while crosslinking with multivalent antigen, which elicited optimal degranulation, caused a distinct aggregation of these signaling chains on the cell membrane. Moreover, only γ- but not β-chains were aggregated during the stimulation that evoked suboptimal secretion. These findings suggest that high-affinity IgE receptor β- and γ-chains do not co-aggregate but for the most part form homogenous aggregates of β-chains or γ-chains after crosslinking.
Cell-specific Processing of Chromogranin A in Endocrine Cells of the Rat Stomach
Authors: Norlén Per , Curry William J. , Björkqvist Maria , Maule Aron , Cunningham Rodat T. , Hogg Robert B. , Harriott Pat , Johnston Colin F. , Hutton John C. , Håkanson Rolf
Published: April 2011

The rat stomach is rich in endocrine cells. The acid-producing (oxyntic) mucosa contains ECL cells, A-like cells, and somatostatin (D) cells, and the antrum harbours gastrin (G) cells, enterochromaffin (EC) cells and D cells. Although chromogranin A (CgA) occurs in all these cells, its processing appears to differ from one cell type to another. Eleven antisera generated to different regions of rat CgA, two antisera generated to a human (h) CgA sequences, and one to a bovine (b) CgA sequence, respectively, were employed together with antisera directed towards cell-specific markers such as gastrin (G cells), serotonin (EC cells), histidine decarboxylase (ECL cells) and somatostatin (D cells) to characterize the expression of CgA and CgA-derived peptides in the various endocrine cell populations of the rat stomach. In the oxyntic mucosa, antisera raised against CgA291–319 and CGA316–321 immunostained D cells exclusively, whereas antisera raised against bCgA82–91 and CgA121–128 immunostained A-like cells and D cells. Antisera raised against CgA318–349 and CgA437–448 immunostained ECL cells and A-like cells, but not D cells. In the antrum, antisera against CgA291–319 immunostained D cells, and antisera against CgA351–356 immunostained G cells. Our observations suggest that each individual endocrine cell type in the rat stomach generates a unique mixture of CgA-derived peptides, probably reflecting cell-specific differences in the post-translational processing of CgA and its peptide products. A panel of antisera that recognize specific domains of CgA may help to identify individual endocrine cell populations.
Demonstration of Acetylcholinesterase Molecular Forms in a Continuous Tubular Lysosomal System of Rat Pancreatic Acinar Cells
Authors: Bendayan Moise , Gisiger Victor
Published: April 2011

By applying the highly sensitive cytochemical Gautron's technique, we were able to reveal AChE activity in rat pancreatic acinar cells, particularly at the level of a complex membrane-bound network formed by tubules with varicosities located around the nuclei and close to the basolateral membrane. The Golgi apparatus was devoid of cytochemical reaction beside the trans-Golgi network cisternae, which showed a positive reaction. The RER of some acinar cells also presented a signal, demonstrating their capability of synthesizing AChE. Immunogold using a specific anti-AChE antibody yielded similar results. Double-labeling experiments corroborated the presence of enzyme cytochemical and immunocytochemical signals in the same lysosomal tubular network. Biochemical sedimentation assays confirmed the presence of AChE in acinar cells, which exists as two globular molecular forms, G1 and G4. These results were obtained with pancreatic tissue in situ as well as with isolated acinar cells maintained in culture and devoid of neural elements. The existence of a continuous tubular lysosomal network containing AChE is in agreement with previous reports on acinar and other cell types, and supports a more general hypothesis on dynamic continuities among cell structures. Whether AChE is being secreted by the acinar cells or internalized through this endo-lysosomal system was not defined. However, the capability of the acinar cells to synthesize AChE and to channel it through a tubular system is a good indication that the cells can modulate their cholinergic stimulation for optimal secretion of digestive enzymes.
Mucin MUC1 Is Seen in Cell Surface Protrusions Together with Ezrin in Immunoelectron Tomography and is Concentrated at Tips of Filopodial Protrusions in MCF-7 Breast Carcinoma Cells
Authors: Bennett Richard , Järvelä Toni , Engelhardt Peter , Kostamovaara Leena , Sparks Pamela , Carpén Olli , Turunen Ossi , Vaheri Antti
Published: April 2011

MUC1, a transmembrane member of the mucin family, is believed to have anti-adhesive properties because of its highly sialylated, extended, and rigid rod-like conformation. The ERM proteins (ezrin, radixin, and moesin) function as membrane–cytoskeletal linkers. MUC1 and ezrin are enriched in microvilli in MCF-7az breast carcinoma cells. Similar localization was also found in peripheral membrane areas and in filopodium-like protrusions. Whereas ezrin was consistently detected in the cell–cell contact region, MUC1 was less frequently found there. MUC1 was distinctly expressed in long filopodial protrusions and was highly concentrated at their tips, which also contained ezrin, whereas F-actin was found along the stalk. This localization of MUC1 suggests a role for MUC1 in transient cell structures of migrating cells and transient cell adhesion. No direct association has yet been found between MUC1 and ezrin. However, both MUC1 and ezrin had a similar overall distribution pattern in microvilli and filopodium-like protrusions in immunoelectron tomography. In addition, MUC1 and ezrin showed spatial association, because several 10-nm gold particles used to decorate ezrin were seen in the vicinity close to the clusters of 5-nm gold particles decorating MUC1. Therefore, MUC1 appears to be associated with ezrin, but the nature of this association requires further study.
Tissue Activity and Cellular Localization of Human Semicarbazide-sensitive Amine Oxidase
Authors: Andrés Noemí , Lizcano José Miguel , Rodríguez Manuel J. , Romera Manuel , Unzeta Mercedes , Mahy Nicole
Published: April 2011

SUMMARY Semicarbazide-sensitive amine oxidase (SSAO), widely distributed in highly vascularized mammalian tissues, metabolizes endogenous and xenobiotic aromatic and aliphatic monoamines. To assess whether its physiological role in humans is restricted to oxidation, we used an immunohistochemical approach to examine the cellular localization of SSAO in human peripheral tissues (adrenal gland, duodenum, heart, kidney, lung, liver, pancreas, spleen, thyroid gland, and blood vessels) and also analyzed its subcellular localization. The results are in agreement with the specific activities also determined in the same samples and are discussed with reference to the tissue distribution of monoamine oxidase A and B. Together with the oxidative deamination of monoamines, SSAO cellular localization indicates that, in most human peripheral tissues, it might participate in the regulation of physiological processes via H2O2 generation. (J Histochem Cytochem 49:209–217, 2001)
In Situ Hybridization and Immunohistochemical Analysis of Cytochrome P450 1B1 Expression in Human Normal Tissues
Authors: Muskhelishvili Levan , Thompson Patricia A. , Kusewitt Donna F. , Wang Charles , Kadlubar Fred F.
Published: April 2011

SUMMARY Cytochrome P450 1B1 (CYP1B1) is a recently cloned dioxin-inducible form of the cytochrome P450 supergene family of xenobiotic-metabolizing enzymes. CYP1B1 is constitutively expressed mainly in extrahepatic tissues and is inducible by aryl hydrocarbon receptor ligands. Human CYP1B1 is involved in activation of chemically diverse human procarcinogens, including polycyclic aromatic hydrocarbons and some aromatic amines, as well as the endogenous hormone 17β-estradiol. The metabolism of 17β-estradiol by CYP1B1 forms 4-hydroxyestradiol, a product believed to be important in estrogen-induced carcinogenesis. Although the distribution of CYP1B1 mRNA and protein in a number of human normal tissues has been well documented, neither the cells expressing CYP1B1 in individual tissue nor the intracellular localization of the enzyme has been thoroughly characterized. In this study, using nonradioactive in situ hybridization and immunohistochemistry, we examined the cellular localization of CYP1B1 mRNA and protein in a range of human normal tissues. CYP1B1 mRNA and protein were expressed in most samples of parenchymal and stromal tissue from brain, kidney, prostate, breast, cervix, uterus, ovary, and lymph nodes. In most tissues, CYP1B1 immunostaining was nuclear. However, in tubule cells of kidney and secretory cells of mammary gland, immunoreactivity for CYP1B1 protein was found in both nucleus and cytoplasm. This study demonstrates for the first time the nuclear localization of CYP1B1 protein. Moreover, the constitutive expression and wide distribution of CYP1B1 mRNA and protein in many human normal tissues suggest functional roles for CYP1B1 in the bioactivation of xenobiotic procarcinogens and endogenous substrates such as estrogens. (J Histochem Cytochem 49:229–236, 2001)
Immunochemical Characterization of a Chicken Egg Yolk Antibody to Secretory Forms of Rat Incisor Amelogenin
Authors: Orsini Giovanna , Lavoie Patrice , Smith Charles E. , Nanci Antonio
Published: April 2011

Amelogenins represent the major component of the organic matrix of enamel, and consist of several intact and degraded forms. A precise knowledge of their respective distributions throughout the enamel layer could provide some insight into their functions. To date, no antibody exists that can selectively detect the secretory forms of amelogenin. In this study we used the chicken egg yolk system to generate an antibody to recombinant mouse amelogenin. Immunoblots of whole homogenates from rat incisor enamel organs and enamel showed that the resulting antibody (M179y) recognized proteins corresponding to the five known secretory forms of rat amelogenin. Immunogold cytochemistry demonstrated that reactivity was restricted to ameloblasts and enamel. Secretory forms of amelogenin persisted in significant amounts throughout the enamel layer. The density of labeling was highest over the surface portion of the enamel layer, but enamel growth sites in this region showed a localized paucity of gold particles. Immunoreactivity was lowest over the mid-portion of the layer and increased moderately near the dentino–enamel junction. These results indicate that intact forms of amelogenin probably have a more complex distribution in the enamel layer than was heretofore suspected.