The diverse biological effects of the hormone somatostatin are mediated by five genetic different receptor subtypes (sst1-sst5), which belong to the superfamily of G-protein coupled receptors with seven transmembrane domains. The sst2 subtype is unique among the somatostatin receptors in its structure, since it is expressed in two protein variants which differ within their carboxy-terminal ends, generated by alternative splicing. Within the 5 untranslated region of the gene two introns separate three transcriptional units with distinct promoters. Due to the latter feature, the sst2 gene is also unique among all somatostatin receptor genes regarding its transcriptional regulation. The three alternative promoters are tissue specifically active and show alternative responsiveness to extracellular signals. The second sst2 promoter is important for expression of the gene in tissues where somatostatin has essential physiological functions, such as brain, pituitary and gastrointestinal tissues. Furthermore,
TY - JOUR. T1 - Cloning and expression of a rat somatostatin receptor enriched in brain. AU - Li, Xiao Jiang. AU - Forte, Michael. AU - North, R. Alan. AU - Ross, Christopher A.. AU - Snyder, Solomon H.. PY - 1992/10/25. Y1 - 1992/10/25. N2 - The tetradecapeptide somatostatin (SRIF) is a hormone release-inhibiting substance that mediates diverse effects in brain and peripheral organs via specific receptors. A cDNA encoding a rat SRIF receptor was identified by use of degenerate oligonucleotide primers and polymerase chain reaction amplification of cDNA prepared from transcripts expressed in rat brain. The complete cDNA encodes a protein of 391 amino acids with seven potential transmembrane domains. Expression of the cDNA product in transfected COS-7 cell lines provides the same high affinity of binding to [125I-Tyr11]SRIF-14 as that of rat cerebral cortex tissues. However, the binding of [125I-Tyr11] SRIF-14 to cloned rat SRIF receptor is not displaced by MK678, a SRIF analog that partially ...
Quantitation of somatostatin receptor type 2 gene expression in neuroblastoma cell lines and primary tumors using competitive reverse transcription-polymerase chain reaction.
TY - JOUR. T1 - Activation of rat thymocytes selectively upregulates the expression of somatostatin receptor subtype-1. AU - Sedqi, M.. AU - Roy, Sabita. AU - Mohanraj, D.. AU - Ramakrishnan, Sundaram. AU - Loh, H. H.. PY - 1996/10/22. Y1 - 1996/10/22. N2 - Somatostatin and other neuropeptides are known to modulate the proliferative capacity of immune cells. In the present study, we investigated the expression of Somatostatin receptor (SSTR) subtypes on rat thymocytes. RT-PCR analysis of fresh thymocytes showed significant levels of transcripts for the SSTR2 whereas transcripts for the SSTR1 and SSTR3 were not detectable. Interestingly, when the thymocytes were activated with low concentration of Phytohemagglutinin and interleukin 1, the transcript for SSTR1 was markedly increased. Lymphokine induced activation of thymocytes selectively upregulated the SSTR1 since, transcripts for SSTR2 remained the same after activation and SSTR3 was not detectable. PCR amplified fragment of SSTR1 from the ...
Introduction: Small intestine neuroendocrine tumors (NETs) comprise well-differentiated NET (benign carcinoid), well-differentiated neuroendocrine carcinoma (malignant carcinoid) and poorly differentiated neuroendocrine carcinoma (NEC). The majority of NET patients have developed liver metastases at the time of diagnosis and surgery is then seldom curative. Novel predictive, diagnostic and prognostic markers are thus needed to improve our capabilities to diagnose and cure these tumors. We have previously identified six novel marker genes for neuroendocrine tumor cells by using Affymetrix microarrays and advanced bioinformatics. One of this markers, the paraneoplastic antigen Ma2 (PNMA2), which is normally expressed only in nervous tissue, can in the process of carcinogenesis be detected in tumors located outside the nervous system. The finding that Ma2 is expressed in small intestine neuroendocrine primary tumors and their metastases made it interesting to screen whether antibodies against Ma2 ...
Ligand-activated somatostatin receptors (SSTRs) initiate cytotoxic or cytostatic antiproliferative signals. We have previously shown that cytotoxicity leading to apoptosis was signaled solely via human (h) SSTR subtype 3, whereas the other four hSSTR subtypes initiated a cytostatic response that led …
TY - JOUR. T1 - Immunohistochemical expression and localization of somatostatin receptor subtypes in androgen ablated prostate cancer. AU - Mazzucchelli, Roberta. AU - Morichetti, Doriana. AU - Santinelli, Alfredo. AU - Scarpelli, Marina. AU - Bono, Aldo V.. AU - Lopez-Beltran, Antonio. AU - Cheng, Liang. AU - Montironi, Rodolfo. PY - 2011/6/1. Y1 - 2011/6/1. N2 - Objective The aim was to examine the expression and localization of the five somatostatin receptors (termed SSTR1 to 5) in radical prostatectomies (RPs) from patients with prostatic adenocarcinoma (PCa) under complete androgen ablation (CAA) before operation. Material The five SSTRs were evaluated in the epithelial, smooth muscle and endothelial cells of normal-looking epithelium (Nep), high-grade prostatic intraepithelial neoplasia (HGPIN) and PCa in 20 RPs with clinically detected PCa from patients under CAA. Twenty RPs with clinically detected PCa from hormonally untreated patients were used as control group. Results Concerning the ...
Somatostatin and its related peptide cortistatin exert multiple biological actions on normal and tumoral tissue targets by interacting with somatostatin receptors (SSTRs). The protein encoded by this gene is one of the SSTRs, which is a multi-pass membrane protein and belongs to the G-protein coupled receptor 1 family. The activity of this receptor is mediated by G proteins which inhibit adenylyl cyclase, and different regions of this receptor molecule are required for the activation of different signaling pathways. A mutation in this gene results in somatostatin analog resistance. Alternatively spliced transcript variants have been identified in this gene.[provided by RefSeq, Feb 2010 ...
A mouse somatostatin (SS) receptor cDNA was cloned from neuroblastoma x glioma (NG108-15) cells. The sequence is almost identical to that of the mouse SSTR2 receptor [(1992) Proc. Natl. Acad. Sci. USA 89, 251)] but lacks about 300 nucleotides between transmembrane domain VII and the C-terminus. This …
The pulsatile nature of GH release is apparently regulated by alternating sequential changes in two hypothalamic hormones, GH releasing hormone (GHRH) and somatostatin. Entrainment of this pulsatility appears to involve GH-mediated negative feedback. Recently a new receptor involved in GH release was cloned. Activation of this receptor by GH-releasing peptides and MK-0677 initiates and amplifies GH pulsatility and is associated with increased Fos immunoreactivity and electrical activity in GHRH containing arcuate neurons. We show that pretreating mice with GH blocks activation of these neurons by MK-0677. Similarly, octreotide inhibited the action of MK-0677. To determine whether this GH-mediated negative feedback on GHRH neurons was direct, or by GH stimulation of somatostatin release from periventricular neurons, we selectively inactivated the gene for one of the five specific somatostatin receptor subtypes (subtype 2). In the knockout mice, both GH and octreotide failed to inhibit MK-0677 ...
TY - JOUR. T1 - Quantitative and functional expression of somatostatin receptor subtypes in human thymocytes. AU - Ferone, Diego. AU - Pivonello, Rosario. AU - Van Martin Hagen, P.. AU - Dalm, Virgil A S H. AU - Lichtenauer-Kaligis, Elgin G R. AU - Waaijers, Marlijn. AU - Van Koetsveld, Peter M.. AU - Mooy, Diana M.. AU - Colao, Annamaria. AU - Minuto, Francesco. AU - Lamberts, Steven W J. AU - Hofland, Leo J.. PY - 2002/11/1. Y1 - 2002/11/1. N2 - We recently demonstrated the expression of somatostatin (SS) and SS receptor (SSR) subtype 1 (sst1), sst2A, and sst3 in normal human thymic tissue and of sst1 and sst2A on isolated thymic epithelial cells (TEC). We also found an inhibitory effect of SS and octreotide on TEC proliferation. In the present study, we further investigated the presence and function of SSR in freshly purified human thymocytes at various stages of development. Thymocytes represent a heterogeneous population of lymphoid cells displaying different levels of maturation and ...
CONTEXT: Pasireotide (SOM230) is a novel multireceptor ligand somatostatin analog with affinity for somatostatin receptor subtypes sst(1-3) and sst(5). Because most GH-secreting pituitary adenomas express sst(2) and sst(5), pasireotide has the potential to be more effective than the sst(2)-preferential somatostatin analogs octreotide and lanreotide. OBJECTIVE: Our objective was to evaluate ...
Title: Somatostatin Receptor-Targeted Anti-Cancer Therapy. VOLUME: 8 ISSUE: 1. Author(s):Li-Chun Sun and David H. Coy. Affiliation:Peptide Research Laboratories, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.. Keywords:Somatostatin, somatostatin receptors, conjugates, cancer therapy, bombesin, luteinizing hormone releasing hormone, LHRH, somatotropin release-inhibiting factor, SRIF, neuroendocrine tumors, lanreotide, octreotide, vapreotide, SSTRs, topotecan, irinotecan, neuroblastoma IMR32, pancreatic cancer CFPAC-1, multi-drug resistance-associated protein, breast cancer-resistant protein, HUVECs, Paclitaxel, 2PTX-OCT, doxorubicin, 2-pyrrolino-DOX, Methotrexate, SSTR-negative CHO cells, combretastatin, colchicine. Abstract: Somatostatin receptors (SSTRs), especially SSTR subtype 2, are found expressed at relatively higher levels in many tumor cells and in tumoral blood vessels relative to normal tissues. This creates an opportunity for developing ...
Introduction: Gastroenteropancreatic neuroendocrine neoplasia (GEP-NENs) are divided on the basis of Ki67 status into G1-G2 neuroendocrine tumors (NETs) (Ki67 ,20%) and neuroendocrine carcinoma (NECs) (Ki67 ,20% ). NEC patients generally have a poor prognosis and the first choice treatment is chemotherapy.A cisplatin/etoposide combination is often used as NECs are considered clinically similar to small cell lung cancer (SCLC), but no literature data is available. There is some evidence to suggest that carboplatin may also be effective in metastatic SCLC ...
Royall, Sophie C. and Fox, D. J. (David J.) (2011) Functionally selective anti-inflammatory ligands for somatostatin receptor sstr(2). American Chemical Society. Abstracts of Papers (at the National Meeting), Vol.241 (No.55-MEDI ). ISSN 0065-7727 ...
Somatostatin receptors are activated by somatostatin secreted from nerve and endocrine cells. The Somatostatin Receptors (SSTRs) are expressed in a tissue-specific manner and involved in the regulation of secretion of insulin, glucagon and growth hormone as well as cell growth induced by neuronal excitation in both the central and peripheral nervous systems. Aberrent expression of somatostatin receptors is known in a large number of human tumours. SSTR2 is expressed in highest levels in the stomach, jejunum, cerebrum, thyroid and kidney.
Rat brain somatostatin (SRIF) receptors were solubilized in an active form with the detergent 3-[(cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). Solubilized SRIF receptors were detected with the stable SRIF analog 125I-MK 678. CHAPS solubilized approximately 30% of membrane-bound SRIF receptors. 125I-MK 678 binding to the solubilized SRIF receptors reached equilibrium by 90 min and dissociated from the receptor with a t1/2 of 60 min. The binding of 125I-MK 678 to the solubilized SRIF receptor was of high affinity and was selective. The characteristics of 125I-MK 678 binding to the solubilized and membrane-bound SRIF receptors were similar. The solubilized brain SRIF receptor specifically bound to a wheat germ agglutinin-Sepharose column, suggesting that it is a glycoprotein. Analysis of the solubilized SRIF receptor by gel exclusion chromatography on an AcA 34 Ultrogel column revealed that its molecular mass is approximately 400 kDa. This mass is probably representative of the ...
Classic somatostatin analogues aimed at somatostatin receptor type 2, such as octreotide and lanreotide, represent the mainstay of medical treatment for acromegaly. These agents have the potential to decrease hormone secretion and reduce tumour size. Patients with a germline mutation in the aryl hydrocarbon receptor-interacting protein gene, AIP, develop young-onset acromegaly, poorly responsive to pharmacological therapy. In this review, we summarise the most recent studies on AIP-related pituitary adenomas, paying special attention to the causes of somatostatin resistance; the somatostatin receptor profile including type 2, type 5 and truncated variants; the role of G proteins in this pathology; the use of first and second generation somatostatin analogues; and the role of ZAC1, a zinc-finger protein with expression linked to AIP in somatotrophinoma models and acting as a key mediator of octreotide response ...
Johnson J, Wong H, Walsh JH, Brecha NC. Expression of the somatostatin subtype 2A receptor in the rabbit retina. J Comp Neurol 1998;393:93-101.. Johnson J, Wu V, Wong H, Walsh JH, Brecha NC. Somatostatin receptor Sst2A expression in the rat retina. Neuroscience 1999;94:675-83.. Akopian A, Johnson J, Gabriel R, Brecha NC, Witkovsky P. Somatostatin modulates voltage-gated K+ and Ca2+ currents in rod and cone photoreceptors of the salamander retina. J Neurosci 2000;20:929-36.. Johnson J, Caravelli ML, Brecha NC. Somatostatin inhibits Ca2+ influx into rat rod bipolar cell axonal terminals. Vis Neurosci 2001;18:101-8.. Cueva JG, Haverkamp S, Reimer RJ, Edwards RH, Wässle H, Brecha NC. The vesicular GABA transporter is expressed by amacrine and horizontal cells. J Comp Neurol (Accepted).. ...
About Crinetics Pharmaceuticals Crinetics Pharmaceuticals is a clinical stage pharmaceutical company focused on the discovery, development, and commercialization of novel therapeutics for rare endocrine diseases and endocrine-related tumors. The companys lead product candidate, CRN00808, is an oral selective nonpeptide somatostatin receptor type 2 biased agonist undergoing two Phase 2 clinical trials for the treatment of acromegaly, an orphan disease affecting more than 25,000 people in the United States. Crinetics second oral product development candidate, CRN01941, has entered the clinic for the treatment of neuroendocrine tumors. The company is also developing oral nonpeptide somatostatin agonists for hyperinsulinism, as well as oral nonpeptide ACTH antagonists for the treatment of Cushings disease. All of the companys drug candidates are new chemical entities resulting from in-house drug discovery efforts. For more information, please visit www.crinetics.com. Forward-Looking Statements ...
AB - The fluorine-18 radiolabelled octreotide derivative [18F]FET-βAG-TOCA targeting somatostatin receptor type 2, has been evaluated clinically for positron emission tomography (PET) imaging of neuroendocrine tumours (NETs). We report an improved automated radiosynthesis of [18F]FET-βAG-TOCA with several advantages over the current automated GMP synthesis: 1) cartridge-based purification of 2-[18F]fluoroethylazide ([18F]FEA); 2) simple set-up for the radiolabelling on a single cassette; 3) HPLC purification using a biocompatible mobile phase. [18F]FET-βAG-TOCA was produced with a radiochemical yield of 16.7 ± 0.6% (non-decay corrected) and radiochemical purity ≥98%. The automated synthesis produced multi-patient doses (900 MBq) that were radiochemically stable (≥98%) over 4 hours. In addition, the automated procedure described can be used, with minimal adaptation, to radiolabel any alkyne-containing peptide with [18F]FEA using the GE FASTlab™ platform ...
Hi folks, I need some help. I am struggling with a double immunostaining for somatostatin receptor and desmin. All my previous double stainings worked beautifully, but they were performed on fresh frozen acetone fixed pancreatic tissue. For staining of somatostatin receptor I have to fix with formaldehyde. I use 20 minutes 0.75% PFA perfused tissue which is snap frozen embedded in tissue freezing medium and cut on a cryostat. I was advised to do it this way to prevent loss of antigenicity. Morphology is quite good. This fixation works for the somatostatin receptor staining, but it kills the desmin signal. I was able to retrieve most of the desmin signal by EIER for 10 minutes with trypsin-EDTA, but now the morphology is awful. Can someone give me some advice? Sincerely yours, Veronique Andriessen BAS Lab. Molecular Liver Cell Biology, Free University Brussels (VUB)Belgium _______________________________________________ Histonet mailing list [email protected] ...
Porcine reproductive and respiratory symptoms (PRRS) is one of the most economically significant viral diseases facing the global swine industry. and rebound (biphasic within 42 dpi). The convenient biological interpretation of the model parameters estimates, allowed us not only to quantify inter-host variation, but also to establish common I-BET-762 viremia curve characteristics and their predictability. Statistical analysis of the profile characteristics revealed that persistent profiles were distinguishable already within the first 21 dpi, whereas it is not possible to predict the onset of viremia rebound. Analysis of the neutralizing antibody(nAb) data indicated that there was a ubiquitous strong response to the homologous PRRSV challenge, but high variability in the range of cross-protection of the nAbs. Persistent pigs were found to have a significantly higher nAb cross-protectivity than pigs that either cleared viremia or experienced rebound within 42 dpi. Our study provides novel ...
The somatostatin (SS) receptor scintigraphy (SRS), using octreotide radiolabelled withIn (Ocreoscan©, OCT), is a consolidated diagnostic procedure in patients with neuroendocrine tumors (NET) because of an increased expression of somatostatin receptors (SS-R) on neoplastic cells. Uptake of SS analogues (SSA) can also be due to SS-R expression on nonmalignant cells when activated as lymphocytes, macrophages, fibroblasts, vascular cells. Because of this uptake, clinical indications can be found either in neoplasms not overexpressing SS-R, as nonsmall cell lung cancer, and in active benign diseases. Read More ...
In octreoscan, octreotide, an analogue of somatostatin, is labeled with a radioactive tracer and injected intravenously; the radioactive octreotide attaches to somatostatin receptors on the tumor cells and can then be observed with a special scanning camera. A variation of nuclear scanning, called single-photon emission computed tomography, or SPECT, enhances the sensitivity of the test.. An OctreoScan may be ordered for the following purposes:. ...
This study aimed at assessing the performance of177Lu-DOTATATE-based peptide receptor radionuclide therapy (PRRT) in de-differentiated thyroid carcinoma thyroglobulin-elevated negative iodine scintigraphy (TENIS) in terms of clinical efficacy and outcome. This is a retrospective analysis of patients of TENIS who had undergone PRRT in a tertiary care setting. The selected patients were analyzed for the following parameters: (i) the patient characteristics, (ii) the metastatic burden, (iii) study of PRRT cycles and activity, (iv) response assessment (undertaken by three-parameter scale: symptomatic including Karnofsky/Lansky Performance scoring, biochemical and scan features) employing predefined criteria (detailed in methods), and (v) Grade III/IV hematological or renal toxicity. According to the qualitative uptake of the tracer in somatostatin receptor (SSTR)-based imaging (with either99mTc-HYNIC-TOC/68Ga-DOTATATE), the lesions were divided into the following four categories: Grade 0: no uptake, ...
Molecular imaging modalities exploit aspects of neuroendocrine tumors (NET) pathophysiology for both diagnostic imaging and therapeutic purposes. The characteristic metabolic pathways of NET determine which tracers are useful for their visualization. In this review, we summarize the diagnostic value of all available molecular imaging studies, present data about their use in daily practice in NET centers globally, and finally make recommendations about the appropriate use of those modalities in specific clinical scenarios. Somatostatin receptor scintigraphy (SRS) continues to have a central role in the diagnostic workup of patients with NET, as it is also widely available. However, and despite the lack of prospective randomized studies, many NET experts predict that Gallium-68 ((68)Ga)-DOTA positron emission tomography (PET) techniques may replace SRS in the future, not only because of their technical advantages, but also because they are superior in patients with small-volume disease, in ...
Polyclonal antibody for SOMATOSTATIN RECEPTOR 1/SSTR1 detection. Host: Rabbit.Size: 100μg/vial. Tested applications: IHC-P. Reactive species: Human. SOMATOSTATIN RECEPTOR 1/SSTR1 information: Molecular Weight: 42686 MW; Subcellular Localization: Cell memb
Depreotide is a peptide analogue of a somatostatin receptor that preferentially binds to somatostatin receptors 2, 3, and 5. Many lung tumors may express these receptors to a greater extent than normal tissue. Depreotide study is a noninvasive, receptor-specific imaging agent that is used to assess malignant versus benign single pulmonary nodules before biopsy.
Somatostatin (SST) is a small cyclic peptide that was first identified as a powerful inhibitor of the secretion of various hormones including growth hormone (GH), thyroid-stimulating hormone (TSH) and prolactin from the pituitary, as well as practically every major hormone from the intestinal tract. SST consists of two major bioactive forms, SST-14 and the N-terminus extended peptide SST-28, that can be produced by a wide variety of neuroendocrine, inflammatory and immune cells. In target cells, SST induces a variety of physiological functions that include neuromodulation, cell secretion, cell proliferation and smooth muscle contractility. SST acts on its multiple cell targets via a family of six receptors that originate from five genes: SSTR1, SSTR2a, SSTR2b, SSTRR3, SSTR4, SSTR5. The SSTRs are members of the G-protein coupled receptor superfamily and they modulate cell response via multiple second messenger systems such as inhibition of adenylate cyclase, modulation of conductance of ion ...
Membrane Target Systems are quality assured frozen membranes from cells that express recombinant or endogenous receptors. We submit every batch of receptor to stringent quality control testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTPgS data is also provided for some of our Gi coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximity methods, such as FlashPlate, or classical filtration methods). Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Certificate of Analysis.. Some of our receptors may be restricted for sale in specified ...
The sst2A diffuses rapidly within the plasma membrane as demonstrated using FRAP analysis of fluorescently tagged receptors. In addition, the percentage of the mobile fraction is very high (,85%) in the three cellular compartments studied. The diffusion characteristics of the sst2A is similar from those reported for other GPCRs in extrasynaptic sites, such as the serotonin 5HT1A (Pucadyil and Chattopadhyay, 2007) and dopamine D1 (Scott et al., 2006) receptors. In spines, although the sst2A receptor has been shown to potentially interact with scaffolding proteins of the postsynaptic density Shank1 and ProSAP1/CortBP1 (Zitzer et al., 1999a,b), our results indicate that, in resting conditions, only a minor portion of sst2A receptors might be associated with cytoskeletal anchoring proteins. However, such interactions often occur when the receptor is stimulated, as previously demonstrated for the sst2A and ProSAP1/CortBP1 (Zitzer et al., 1999a) or for the β-adrenergic receptor and the PDZ ...
SS analogs may be of interest in the treatment of lymphoproliferative malignancies, although controlled studies are warranted to investigate the efficacy of the current available analogs. A promising approach in refractory patients with SSR positive malignant lymphomas may be radionuclide-targeted therapy. Furthermore, the development of receptor-based localization and antitumor strategies may be extended to other G protein-coupled receptors. This could be valid for two different important reasons: first, neuropeptide receptors homo- and heterodimerization has been recently shown occurring in transfected cell lines and involves different subtypes of SSR, as well as SSR and receptors for dopamine (50-61). Dimer formation seems to enhance or modify the transduction pathway activated by the monomeric receptor. From the other hand, in vivo imaging techniques of tumor via receptors for other well known neuroeptides, such as bombesin, vasoactive intestinal polypeptide, substance P, gastrin, have been ...
transmembrane receptor for somatostatin; coupled to a G-protein which inhibits adenylyl cyclase; may also activate the mitogen-activated protein (MAP) kinase cascade
Purpose. Grade 3 NENs are aggressive tumours with poor prognosis. PRRT+/− radiosensitising chemotherapy is a potential treatment for disease with high somatostatin receptor (SSTR) expression without spatially discordant FDG-avid disease. We retrospectively evaluated the efficacy of PRRT in G3 NEN.. Methods. Kaplan-Meier estimation was used to determine progression-free survival (PFS) and overall survival (OS) defined from start of PRRT. Subgroup analysis was performed for patients with Ki-67 ≤ 55% and ,55%. Anatomical response (RECIST 1.1) and toxicity 3 months after PRRT was determined. Disease control rate (DCR) was defined as complete response (CR), partial response (PR) and stable disease (SD) of those with prior progression.. Results. 28 patients (M = 17; age 16-78 years; Ki-67 ≤ 55% = 22) were reviewed. 17 patients had pancreatic, 5 small bowel, 3 large bowel, 2 bronchial and 1 unknown primary disease. 25/28 had significant FDG-avid disease prior to treatment. Most had ...
The work of prof emeritus Sharon Stone-Elander is continued in the group, where radiotracer development and validation, and positron emission tomography (PET) in animal models of stroke, inflammation and cancer are areas of study. The group also has a significant clinical responsibility of radiotracer production for Karolinska University Hospital as well as other hospitals in the region. Examples of produced radiotracers and areas of study include: 18F-FDG (glucose metabolism), 11C-methionine (amino acids), 11C-acetate (fatty acids), 18F-NAF (skeletal diseases), 18F-FLT (cell proliferation), 18F-FMISO (hypoxia), 68Ga-DOTATOC (NET/somatostatin receptor), 68Ga-PSMA (prostate cancer).. ...
Rabbit polyclonal Somatostatin Receptor 3 antibody validated for WB, IHC, ICC and tested in Human. Referenced in 3 publications. Immunogen corresponding to…
Product Name: PrEST Antigen ZSWIM4Synonym: FLJ12221Product Type: ChemicalCAS NO: 1404095-34-6Somatostatin Receptor inhibitorsAssay: |80%
Human SSTR1 partial ORF ( AAH35618, 1 a.a. - 60 a.a.) recombinant protein with GST-tag at N-terminal. (H00006751-Q01) - Products - Abnova
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Neuroendocrine tumors (NETs) are rare tumours arising from the gastroenteropancreatic axis. They are slow growing and often metastatic. Diagnostic workup requires imaging; both anatomical (ultrasound, CT, MRI) and functional (somatostatin receptor scintigraphy, PET).. NETs strongly express somatostatin receptors (SSTRs) of five different subtypes (SSTRs1 5) with SSTR2 being the most common. Some NETs reflect hyperactivity of the guanethidine pathway. Imaging based on receptor expression helps to guide treatment in cases of inoperable or progressive NETs. Imaging with radiolabelled receptor binding somatostatin analogues and meta isobenzyl guanidine (MIBG) can be used to select patients for peptide receptor radionuclide therapy (PRRT).. We describe two cases with differential uptake patterns on 123I-MIBG, 111In octreotide and 111In DOTATOC scanning affecting treatment options.. Case 1 20 years old male referred for PRRT with metastatic gastric small cell NET.111In octreotide scan showed a focal ...
This study characterises the somatostatin binding site in human gastrointestinal cancer and mucosa in terms of cationic specificity and relative affinity for three somatostatin analogues. Competitive displacement assays were performed on plasma membranes from human gastric and colonic tissues using radiolabelled somatostatin-14 as ligand. Comparison was made with the somatostatin binding site in rat cerebral cortex. In gastrointestinal tissue, magnesium decreased and sodium increased specific binding. By contrast, in rat cerebral cortex, the converse cationic effect was seen. These changes resulted from alterations in receptor density, with no change in receptor affinity. Displacement studies were then performed with somatostatin-14 and somatostatin analogues RC-160, somatuline, and octreotide. RC-160 and somatuline displaced radiolabel from binding sites in gastric and colonic cancer and mucosa with 10-fold lower affinity than the native peptide. Octreotide did not displace radioligand in ...
Idiopathic pulmonary fibrosis prognosis remains severe, in particular for IPF, the most common entity. Moreover, current treatment options are largely ineffective and do not change the natural course of the disease. Pre-clinical evidence supports somatostatin receptors expression in the lung of patients with IPF. Recently new PET tracers (Somatostatin analogues labelled with 68Gallium), specifically binding to somatostatin receptors, have been developed and are used in neuroendocrine tumours clinical trials.. Aim of the present study is to evaluate the role of 68Ga-DOTA-NOC PET/CT in patients with idiopathic pulmonary fibrosis, in particular in patients with IPF/UIP and in cases with NSIP, that are characterized by a more indolent progression. PET/CT data will be compared with HRCT findings for the early detection of fibrotic areas and to non-invasively assess somatostatin receptors expression at lung level in these patients, with potential therapeutic implications. Moreover, the SUVmax (maximum ...
First-generation somatostatin receptor ligands (fg-SRLs) represent the mainstay of medical therapy for acromegaly, but they provide biochemical control of disease in only a subset of patients. Various pre-treatment biomarkers might affect biochemical response to fg-SRLs.To identify clinical predictors of the biochemical response to fg-SRLs monotherapy defined as biochemical- (IGF-1 ≤1.3 x upper limit of normal; ULN), partial- (,20% relative IGF-1 reduction without normalization) and non-response (≤20% relative IGF-1 reduction), and IGF-1 reduction.Retrospective multicenter study.Eight participating European centers.We performed a meta-analysis of participant data from two cohorts (Rotterdam and Liège acromegaly survey (LAS), 622 out of 3520 patients). Multivariable regression models were used to identify predictors of biochemical response to fg-SRL monotherapy.Lower IGF-1 concentration at baseline (OR=0.82, [0.72-0.95] IGF-1 ULN, p=0.0073) and lower bodyweight (OR=0.99, [0.98-0.99] kg, ...
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OBJECTIVE: To evaluate the effectiveness of the treatment of acromegaly patients at the Federal University of Triangulo Mineiro. METHODS: Cross-sectional and retrospective study of thirty cases treated over a period of two decades. RESULTS: 17 men (56.7%) aged 14-67 years and 13 women aged 14-86 years were analyzed. Twenty-one patients underwent transphenoidal surgery, whichwas associated with somatostatin receptor ligands in 11 patients (39.3%), somatostatin receptor ligands + radiotherapyin 5 patients (17.8%), radiotherapy in 3 patients (10.7%), and radiotherapy + somatostatin receptorligands + cabergoline in 1 patient (3.6%). Additionally, 2 patients underwent radiotherapy and surgeryalone. Six patients received somatostatin receptor ligands before surgery, and 2 were not treated due to refusal and death. Nine patients have died, and 20 are being followed; 13 (65%) have growth hormonelevels o1 ng/mL, and 11 have normal insulin-like growth factor 1 levels. CONCLUSION: The current treatment
TY - JOUR. T1 - Somatostatin can locally inhibit proliferation and differentiation of cartilage and bone precursor cells. AU - Weiss, Roy E.. AU - Reddi, A Hari. AU - Nimni, M. E.. PY - 1981/12. Y1 - 1981/12. N2 - The influence of somatostatin on discrete stages of collagenous-matrix-induced endochondral bone formation has been investigated. Local injection of somatostatin, i.e., without any measurable systemic effect, resulted in a 75% reduction of cell proliferation as measured by [3H]thymidine incorporation and ornithine decarboxylase activities. The minimum effective inhibitory dose of somatostatin was 0.25 μg/day. Twice daily local injections of the hormone during cartilage formation also resulted in an inhibition, but this was shown to be due to impaired cell proliferation rather than to a direct effect of somatostatin on differentiation. Injection of somatostatin into developing bone tissue after the cartilage stage impaired osteogenesis, assessed by45Ca incorporation and alkaline ...
Somatostatin Receptor Scintigraphy (using radiolabeled octreotide) is similar to whole body bone scan and images are acquired through a gamma camera. Modern scintigraphy techniques (eg. SPECT) allow 3D localisation of areas of uptake. SRS is useful for detection of primary disease and metastatic sites, although modern cross sectional imaging also capable of doing this. Scintigraphy techniques are limited by the general poor resolution of nuclear medicine techniques (poor detection of tumours , 1 cm ...
Somatostatin, a hormone that signals via Gi/Go, usually inhibits increases in intracellular calcium concentration ([Ca2+]i) and insulin release from β-cells. We have found that in the presence of arginine vasopressin (AVP), which signals via Gq, somatostatin increased [Ca2+]i, leading to insulin release in HIT-T15 cells. The increase in [Ca2+]i by somatostatin was observed even after 60min of AVP treatment. Somatostatin alone failed to increase [Ca2+]i and insulin release. Somatostatin induced changes in [Ca2+]i in a biphasic pattern, characterized by a sharp and transient increase followed by a rapid decline to sub-basal levels. Pretreatment with pertussis toxin, which inactivates Gi/Go, abolished the effects of somatostatin. U-73122, an inhibitor of phospholipase C, antagonized the somatostatin-induced increase in [Ca2+]i. In Ca2+-free medium, somatostatin still increased [Ca2+]i. Depletion of intracellular Ca2+ stores with thapsigargin, a microsomal Ca2+-ATPase inhibitor, abolished ...
TY - JOUR. T1 - Hypothalamic interconnections of somatostatin and growth hormone releasing factor neurons. AU - Willoughby, J. O.. AU - Brogan, M.. AU - Kapoor, R.. PY - 1989. Y1 - 1989. N2 - Combined immunohistochemical labelling for neurons containing growth hormone (GH) releasing factor (GRF) or somatostatin and single labelling immunohistochemistry combined with Fluorogold retrograde transport labelling were used to examine whether somatostatin or GRF neurons might be reciprocally innervated. Occasional somatostatin-immunoreactive neurons in the periventricular preoptic area were found to be closely approached by GRF-immunoreactive fibres, providing possible evidence of scant innervation of somatostatin neurons by GRF cells. In contrast, many GRF-immunoreactive neurons in the arcuate nucleus appeared to have somatostatin-immunoreactive fibres closely applied to their perikarya suggesting that GRF neurons might be innervated by somatostatin cells. Combined retrograde tracing and fluorescence ...