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1.
J Mol Graph Model ; 116: 108254, 2022 11.
Article in English | MEDLINE | ID: mdl-35803082

ABSTRACT

Calcitonin gene-related peptide receptor (CGRPR) is a heterodimer consisting of CLR and RAMP1 proteins. Activation of the CGRPR with the endogenous peptide CGRP is known to play a crucial role in migraine pathophysiology. CGRP occupies two regions in the CGRPR upon binding, namely ectodomain and transmembrane sites (sites 1 and 2, respectively). The disruption of the CGRPR heterodimer interface is one of the main strategies to prevent CGRPR activation and its resulting effects. So far, FDA approved monoclonal antibodies and small molecule gepant inhibitors are considered for the treatment of acute or chronic migraine symptoms. However, most of these gepants have severe side effects. Thus, in this study, a virtual drug repurposing approach is applied to CGRPR to find alternative or better molecules that would have a potential to inhibit or block the CLR - RAMP1 interface compared to known gepant molecules. A small molecule library of FDA-approved molecules was screened in these two different binding sites, further simulations were performed and analyzed. The objectives of this study are (i) to repurpose an FDA-approved drug having more potent features for CGRPR inhibition compared to gepants, and (ii) to examine whether the transmembrane binding site (site 2) accepts small molecules or small peptide analogues for binding. As a result of this extensive in silico analysis, two molecules were identified, namely pentagastrin and leuprorelin. It is shown that FDA approved compound rimegepant and the identified pentagastrin molecules form and maintain the interactions through CLR W72 and RAMP1 W74, which are the residues revealed to have an important role in CGRPR antagonism at binding site 1. At binding site 2, the interactions needed to be formed for CGRP binding are not captured by rimegepant nor leuprorelin, yet leuprorelin forms more interactions throughout the simulations, meaning that small molecules are also capable of binding to site 2. Moreover, it is found that the crucial interactions for receptor signaling and heterodimerization occurred between CLR and RAMP1 interface are disrupted more with the ligands bound to ectodomain site, rather than the transmembrane domain. These findings of pentagastrin and leuprorelin molecules are recommended to be considered in further de novo drug development and/or experimental studies related to CGRPR signaling blockade and antagonism.


Subject(s)
Calcitonin Gene-Related Peptide Receptor Antagonists , Receptors, Calcitonin Gene-Related Peptide , Calcitonin Gene-Related Peptide/chemistry , Calcitonin Gene-Related Peptide/metabolism , Calcitonin Receptor-Like Protein/metabolism , Drug Repositioning , Leuprolide , Pentagastrin , Receptor Activity-Modifying Protein 1/metabolism , Receptors, Calcitonin Gene-Related Peptide/chemistry , Receptors, Calcitonin Gene-Related Peptide/metabolism
2.
Molecules ; 26(12)2021 Jun 11.
Article in English | MEDLINE | ID: mdl-34208385

ABSTRACT

African swine fever virus (ASFV) causes a highly contagious and severe hemorrhagic viral disease with high mortality in domestic pigs of all ages. Although the virus is harmless to humans, the ongoing ASFV epidemic could have severe economic consequences for global food security. Recent studies have found a few antiviral agents that can inhibit ASFV infections. However, currently, there are no vaccines or antiviral drugs. Hence, there is an urgent need to identify new drugs to treat ASFV. Based on the structural information data on the targets of ASFV, we used molecular docking and machine learning models to identify novel antiviral agents. We confirmed that compounds with high affinity present in the region of interest belonged to subsets in the chemical space using principal component analysis and k-means clustering in molecular docking studies of FDA-approved drugs. These methods predicted pentagastrin as a potential antiviral drug against ASFVs. Finally, it was also observed that the compound had an inhibitory effect on AsfvPolX activity. Results from the present study suggest that molecular docking and machine learning models can play an important role in identifying potential antiviral drugs against ASFVs.


Subject(s)
African Swine Fever Virus/drug effects , African Swine Fever/drug therapy , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Machine Learning/standards , African Swine Fever/immunology , African Swine Fever/virology , African Swine Fever Virus/immunology , African Swine Fever Virus/isolation & purification , Amino Acid Sequence , Animals , DNA-Directed DNA Polymerase/chemistry , DNA-Directed DNA Polymerase/metabolism , Drug Design , Molecular Docking Simulation , Pentagastrin/chemistry , Pentagastrin/pharmacology , Swine , Viral Proteins/chemistry , Viral Proteins/metabolism
3.
Curr Drug Metab ; 22(5): 363-371, 2021.
Article in English | MEDLINE | ID: mdl-33511926

ABSTRACT

BACKGROUND: Fixed-dose combination of artemisinin and naphthoquine (NQ) is a new artemisinin- based combination therapy for the treatment of uncomplicated Plasmodium falciparum. NQ absorption has been reported to be affected by food in humans. OBJECTIVES: The effect of gastric pH on NQ pharmacokinetics and antiplasmodial activity was investigated. METHODS: The pharmacokinetic profiles of NQ were studied in healthy rodents after an oral dose of NQ with or without gastric pH modulators, i.e., pentagastrin (stimulator) and famotidine (suppressant). The effect of gastric pH on NQ exposures in humans was predicted using a physiologically-based pharmacokinetic (PBPK) model. The effect of gastric pH on the antiplasmodial activity of NQ was evaluated in mice infected with Plasmodium yoelii. RESULTS: Neither pentagastrin nor famotidine affected NQ absorption (AUC0-t and Cmax) significantly (P > 0.05) in rodents. The predicted PK profiles of NQ in humans did not show an effect of gastric pH. Compared to pure NQ (ED90, 1.2 mg/kg), the combination with pentagastrin showed non-significantly (< 1.5-fold) higher antimalarial potency (ED90, 1.1 mg/kg). Correspondingly, the elevation of gastric pH (up to pH 5) by famotidine treatment resulted in a relatively weaker antimalarial potency for NQ (ED90, 1.4 mg/kg). Such a difference is within the acceptable range of variability in NQ pharmacokinetics and antiplasmodial activity. CONCLUSIONS: Although the food was found to significantly impact NQ pharmacokinetics, other factors except for gastric pH should account for the result, and the warning of careful use of NQ in patients with the acid-related disease is not expected to be clinically meaningful.


Subject(s)
1-Naphthylamine/analogs & derivatives , Aminoquinolines/pharmacokinetics , Antimalarials/pharmacokinetics , Famotidine/pharmacology , Pentagastrin/pharmacology , 1-Naphthylamine/pharmacokinetics , Aminoquinolines/blood , Animals , Artemisinins/pharmacology , Computer Simulation , Drug Combinations , Humans , Hydrogen-Ion Concentration , Malaria/drug therapy , Male , Mice , Mice, Inbred ICR , Models, Animal , Rats , Rats, Wistar
4.
Turk J Med Sci ; 51(2): 650-656, 2021 04 30.
Article in English | MEDLINE | ID: mdl-33128357

ABSTRACT

Background/aim: Medullary thyroid cancer (MTC) originates from parafollicular cells (C cell) and produces calcitonin (CT). Basal serum CT was used in the diagnosis and treatment of MTC. If basal CT level is 100 pg/mL or higher, it is likely to have MTC, but if basal CT level is below 10 pg/mL, the probability of developing thyroid disease is low. In cases with basal CT level between 10­100 pg/mL, pentagastrin-stimulated (PS) CT level is studied to evaluate MTC and C cell hyperplasia (CHH). This study aimed to determine cut-off value for basal and PS peak CT level for diagnosis of MTC. Materials and methods: We retrospectively reviewed files of patients presented to endocrine outpatient clinic of Ege University, Medicine School, between 2010 and 2019; 176 patients with basal CT level of 10­100 pg/mL and patients with PS test were included to the study. Results: The receiver operating characteristic curve (ROC) analysis was used to determine cut-off value for basal CT that can discriminate cases with MTC and those with nodular goiter. Cut-off value for basal CT was calculated as 46.5 pg/mL (specificity; 100 %, sensitivity; 74 %). In the ROC analysis for peak PS CT, cut-off value was calculated as 285 pg/mL (specificity:100 %; sensitivity:82 %). When peak CT level was > 290 pg/mL in PS test, both specificity and sensitivity for MTC were determined as 100 %. The PS peak CT level > 285 pg/ mL was significant for MTC diagnosis while range of 117­274 pg/mL was significant for CHH. Conclusion: In this study, cut-off value was calculated as 46.5 pg/mL for basal CT, whereas 285 pg/mL for PS peak CT in the diagnosis of preoperative MTC.


Subject(s)
Calcitonin/blood , Carcinoma, Medullary/diagnosis , Carcinoma, Neuroendocrine/diagnosis , Thyroid Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/blood , Carcinoma, Medullary/blood , Carcinoma, Medullary/surgery , Carcinoma, Neuroendocrine/blood , Carcinoma, Neuroendocrine/surgery , Female , Goiter/blood , Goiter/diagnosis , Graves Disease/blood , Graves Disease/diagnosis , Humans , Male , Middle Aged , Pentagastrin/blood , Predictive Value of Tests , Retrospective Studies , Thyroid Gland/pathology , Thyroid Neoplasms/blood , Thyroid Neoplasms/surgery
5.
J Mol Graph Model ; 101: 107730, 2020 12.
Article in English | MEDLINE | ID: mdl-32920239

ABSTRACT

The SARS-CoV-2 main protease (Mpro) is an attractive target towards discovery of drugs to treat COVID-19 because of its key role in virus replication. The atomic structure of Mpro in complex with an α-ketoamide inhibitor (Lig13b) is available (PDB ID:6Y2G). Using 6Y2G and the prior knowledge that protease inhibitors could eradicate COVID-19, we designed a computational study aimed at identifying FDA-approved drugs that could interact with Mpro. We searched the DrugBank and PubChem for analogs and built a virtual library containing ∼33,000 conformers. Using high-throughput virtual screening and ligand docking, we identified Isavuconazonium, a ketoamide inhibitor (α-KI) and Pentagastrin as the top three molecules (Lig13b as the benchmark) based on docking energy. The ΔGbind of Lig13b, Isavuconazonium, α-KI, Pentagastrin was -28.1, -45.7, -44.7, -34.8 kcal/mol, respectively. Molecular dynamics simulation revealed that these ligands are stable within the Mpro active site. Binding of these ligands is driven by a variety of non-bonded interaction, including polar bonds, H-bonds, van der Waals and salt bridges. The overall conformational dynamics of the complexed-Mpro was slightly altered relative to apo-Mpro. This study demonstrates that three distinct classes molecules, Isavuconazonium (triazole), α-KI (ketoamide) and Pentagastrin (peptide) could serve as potential drugs to treat patients with COVID-19.


Subject(s)
Cysteine Endopeptidases/chemistry , Nitriles/pharmacology , Pentagastrin/pharmacology , Protease Inhibitors/pharmacology , Pyridines/pharmacology , Triazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Catalytic Domain , Computer Simulation , Coronavirus 3C Proteases , Cysteine Endopeptidases/metabolism , Databases, Pharmaceutical , Drug Approval , Drug Discovery , Drug Repositioning , High-Throughput Screening Assays/methods , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , Nitriles/chemistry , Pentagastrin/chemistry , Protease Inhibitors/chemistry , Pyridines/chemistry , Triazoles/chemistry , United States , United States Food and Drug Administration , Viral Nonstructural Proteins/metabolism
6.
Int J Pharm ; 565: 9-19, 2019 Jun 30.
Article in English | MEDLINE | ID: mdl-31047995

ABSTRACT

Microneedle technology offers a viable means of delivering biologically active pharmaceutical agents across the skin in a minimally invasive and virtually pain free manner. Previous work detailed the first successful transdermal delivery of a model peptide drug, polymyxin b, utilising a dissolving polymer-based microneedle system. The focus of this study was to examine the ability of a dissolving microneedle system to deliver a range of peptides of different sizes and properties. Analogue versions of 2 existing therapeutic peptides; pentagastrin and sincalide, were synthesised utilising Fmoc based solid phase peptide synthesis (SPPS) chemistry techniques and once successfully synthesised and purified, the peptide analogues were characterised using LC-MS. The peptide analogues were then incorporated into PVP/trehalose microneedle formulations. Skin permeation testing, in addition to skin penetration testing, was carried out to determine the effectiveness of the microneedle system to deliver the peptide analogues through porcine skin. The results obtained from these studies were then compared with the permeation results obtained utilising polymyxin B as the peptide drug cargo to evaluate the PVP/trehalose microneedle system's suitability to successfully deliver therapeutic peptides. Results indicated that the microneedle system successfully systemically delivered a higher overall percentage of the encapsulated peptides at an initially faster rate than peptide loaded control discs and in therapeutically relevant concentrations.


Subject(s)
Drug Delivery Systems , Needles , Pentagastrin/administration & dosage , Sincalide/administration & dosage , Administration, Cutaneous , Animals , Female , Male , Microinjections , Polymyxin B/administration & dosage , Skin/metabolism , Skin Absorption , Solubility , Swine
7.
Eur J Pharm Biopharm ; 136: 221-230, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30703546

ABSTRACT

In preclinical research, Beagle dogs are an important model for formulation development and for evaluation of food effects on drug absorption. In this study, the gastrointestinal transit conditions in Beagle dogs were studied with a telemetric motility capsule at different intake conditions. In a cross-over study design, the SmartPill® was given to six Beagle dogs to measure transit times, pH values, pressures and temperatures in the different parts of the canine GI tract. Moreover, the effects of commonly applied pre-treatments as with pentagastrin and famotidine on GI transit conditions were investigated. The gastric transit time in fasted state was short (0.57 ±â€¯0.37 h) and only slightly affected by the pre-treatments. In fed state, gastric transit was clearly prolonged (2.94 ±â€¯0.91 h). The mean intestinal transit time was in the range of 1-2 h and not affected by the intake conditions. The gastric pH values in fasted and fed Beagle dogs were highly variable, but pre-treatment with pentagastrin and famotidine clearly decreased variability. Pre-treatment with pentagastrin resulted in minimum pH values around 0.5 pH units lower than without pre-treatment. Oral administration of famotidine led to constantly elevated pH values of pH 7-8. The maximum pressures in the canine GI tract did not vary significantly between the study arms and typically, maximum pressures of up to 800 mbar were observed in the stomach. The comparison of the data from this study with recent SmartPill® data from humans revealed that major differences could be observed with respect to gastric transit times in fed state, small intestinal transit times as well as maximum pressures arising during GI transit. These differences should be kept in mind if the dog model is used to assess the in vivo performance of solid oral dosage forms intended for use in humans.


Subject(s)
Gastrointestinal Absorption/physiology , Gastrointestinal Transit/physiology , Pentagastrin/administration & dosage , Telemetry/methods , Administration, Oral , Animals , Capsules , Cross-Over Studies , Dogs , Female , Gastrointestinal Absorption/drug effects , Gastrointestinal Transit/drug effects , Humans , Male , Pentagastrin/pharmacokinetics , Telemetry/instrumentation
8.
Acta Biomed ; 89(8-S): 53-57, 2018 12 17.
Article in English | MEDLINE | ID: mdl-30561418

ABSTRACT

Methods for the measure of gastric acid secretion include invasive and non-invasive tests. The gold-standard to measure the acid output is the collection of gastric after in basal condition (Basal Acid Output, B.A.O.) and after an i.m. injection of pentagastrin (Maximal Acid Output, M.A.O.). However, direct measurement of gastric acid production is out of order in clinical practice, but many GI symptoms are claimed to be related with acid disorders and empirically cured. Hypochlorhydria is associated with precancerous conditions such as chronic atrophic gastritis (CAG). Acid measurement with non-invasive methods (pepsinogens) is supported by international guidelines.


Subject(s)
Achlorhydria/diagnosis , Gastric Acidity Determination , Gastrins/blood , Pepsinogens/blood , Achlorhydria/blood , Achlorhydria/physiopathology , Biomarkers , Gastric Acid/metabolism , Gastritis, Atrophic/blood , Gastritis, Atrophic/diagnosis , Gastritis, Atrophic/physiopathology , Humans , Pentagastrin/pharmacology , Peptic Ulcer/physiopathology , Precancerous Conditions/blood , Precancerous Conditions/diagnosis , Precancerous Conditions/physiopathology
9.
J Pharmacol Exp Ther ; 364(2): 275-286, 2018 02.
Article in English | MEDLINE | ID: mdl-29180359

ABSTRACT

Tegoprazan [(S)-4-((5,7-difluorochroman-4-yl)oxy)-N,N,2-trimethyl-1H-benzo[d]imidazole-6-carboxamide], a potassium-competitive acid blocker (P-CAB), is a novel potent and highly selective inhibitor of gastric H+/K+-ATPase. Tegoprazan inhibited porcine, canine, and human H+/K+-ATPases in vitro with IC50 values ranging from 0.29 to 0.52 µM, while that for canine kidney Na+/K+-ATPase was more than 100 µM. A kinetic analysis revealed that tegoprazan inhibited H+/K+-ATPase in a potassium-competitive manner and the binding was reversible. Oral single administrations of tegoprazan ranging from 0.3 to 30 mg/kg in dogs were well absorbed into the blood stream and distributed in gastric tissue/fluid higher than in plasma. Tegoprazan potently inhibited histamine-induced gastric acid secretion in dogs, and a complete inhibition was observed at 1.0 mg/kg starting from 1 hour after administration. Moreover, an oral administration of tegoprazan at 1 and 3 mg/kg reversed the pentagastrin-induced acidified gastric pH to the neutral range. Interestingly, 3 mg/kg tegoprazan immediately evoked a gastric phase III contraction of the migrating motor complex in pentagastrin-treated dogs and similar effects was observed with the other P-CAB, vonoprazan. Tegoprazan is the novel P-CAB that may provide a new option for the therapy of gastric acid-related and motility-impaired diseases.


Subject(s)
Benzene Derivatives/pharmacology , Chromans/pharmacology , Gastric Acid/metabolism , Gastrointestinal Motility/drug effects , Imidazoles/pharmacology , Potassium/metabolism , Proton Pump Inhibitors/pharmacology , Animals , Chromans/metabolism , Dogs , Gastric Juice/drug effects , Gastric Juice/metabolism , H(+)-K(+)-Exchanging ATPase/metabolism , HEK293 Cells , Humans , Hydrogen-Ion Concentration , Imidazoles/metabolism , Pentagastrin/pharmacology , Proton Pump Inhibitors/metabolism , Stomach/drug effects , Stomach/physiology , Swine
10.
Eur Neuropsychopharmacol ; 27(1): 59-69, 2017 01.
Article in English | MEDLINE | ID: mdl-27887860

ABSTRACT

Panic disorder is characterized by the paroxysmal occurrence and fear of bodily symptoms. In recent years it has been proposed that patients "learn" to fear cardiorespiratory sensations through interoceptive conditioning. This study sought to model the initial stage of this process in healthy volunteers (N=44) using mild cardiac sensations. An additional aim was to explore whether anxiety sensitivity - a known risk factor for panic disorder - modulates such interoceptive learning. Infusions of pentagastrin and saline were used to manipulate the presence versus absence of cardiac sensations, respectively, and served as conditioned stimuli in a differential interoceptive conditioning paradigm. Inhalation of 35% CO2-enriched air served as the panicogenic, unconditioned stimulus (UCS). In half of the participants ("prepared" condition), cardiac sensations caused by pentagastrin were followed by inhalation of CO2-enriched air (penta CS+), whereas the absence of such sensations (saline) was followed by room air (saline CS-). The reversed combination ("unprepared" condition) was used in the other half of the participants. Conditioning effects showed up for self-reported UCS-expectancy, but not for skin conductance and anxiety ratings. Only participants from the prepared group learned to expect the UCS, and differential learning was impaired with higher scores on anxiety sensitivity. Expectancy learning was more easily established towards the presence compared to the absence of cardiac sensations, whereas the reverse effect was observed for safety learning. Modeling impaired discriminatory learning and the moderating effect of anxiety sensitivity provides new insight in the development of panic disorder.


Subject(s)
Anxiety/etiology , Conditioning, Classical , Models, Theoretical , Somatoform Disorders/complications , Somatoform Disorders/psychology , Adult , Aged , Carbon Dioxide/administration & dosage , Electrocardiography , Female , Galvanic Skin Response , Humans , Male , Middle Aged , Pentagastrin/administration & dosage , Psychiatric Status Rating Scales , Self Report , Somatoform Disorders/etiology , Young Adult
11.
Article in English | WPRIM (Western Pacific) | ID: wpr-170003

ABSTRACT

PURPOSE: To evaluate the diagnostic accuracy of routine calcitonin measurement in patients with nodular thyroid disease. METHODS: Consecutive patients with nodular thyroid disease (n = 640) were studied. Serum calcitonin levels were measured under basal conditions, and when basal values were between 10–100 pg/mL, testing was repeated after pentagastrin (PG) stimulation. Patients with previously diagnosed or familial medullary thyroid cancer (MTC) were excluded. Patients were operated on when basal or stimulated calcitonin >100 pg/mL or when other surgical indications were present. RESULTS: Four cases of MTC were identified. MTC was diagnosed in 75% of patients with basal calcitonin >100 pg/mL. One out of 11 patients with basal calcitonin between 10–100 pg/mL was diagnosed with MTC. PG stimulation resulted in elevation in 4 cases, where 1 case was diagnosed with MTC. Positive predictive value for basal calcitonin levels in the preoperative diagnosis of MTC was 5% for values between 10–100 pg/mL and 100% for values >100 pg/mL. Possible reasons for false positivity were papillary thyroid cancer in 17%, renal insufficiency in 8.3%, Hashimoto thyroiditis in 17% and β-blocker use in 33%. Positive predictive value for the PG test (>100 pg/mL) was 25% in the entire series. The cost of adding calcitonin measurement (±PG stimulation) to the preoperative work-up, resulted in €912.68 per MTC patient to detect the disease. CONCLUSION: Basal calcitonin measurement together with PG stimulation in cases of basal calcitonin >10 pg/mL detects MTC in 0.62% of patients with nodular thyroid disease.


Subject(s)
Humans , Calcitonin , Diagnosis , Hashimoto Disease , Pentagastrin , Renal Insufficiency , Thyroid Diseases , Thyroid Gland , Thyroid Neoplasms , Thyroid Nodule
12.
Neuro Endocrinol Lett ; 37(7): 485-490, 2016 Dec.
Article in English | MEDLINE | ID: mdl-28326742

ABSTRACT

OBJECTIVES: The aim of the study was to compare the calcitonin (CT) stimulation tests with tests of calcium gluconate (CaG) and pentagastrin (PG), their tolerance and usefulness of PCT in the patients' diagnosis with active Medullary thyroid cancer (MCT) after thyroidectomy. METHODS: CT was marked in serum by the immunosorbent sandwich test. PCT was marked by the immunosorbent sandwich test, with the final reading of fluorenscence. PG was given intravenously at a dose of 0.5 mg/kg body weight for 10 seconds. CaG was also given by intravenous injection at a dose of 2.5 mg of elemental Ca/kg body weight at a rate of 5ml/min, for minimum 3 minutes. Blood was taken at the 0 minute, the 3 and 5 minute after getting the stimulating substances. RESULTS: The post-stimulation CT concentration in the 3 and 5 minute of the CaG test vs PG is significantly higher compared to the baseline. The maximal stimulation of the CT is in the 3 minute, but higher concentrations occurred using the CaG. CONCLUSION: The results of the study suggest a similar diagnostic value of the tests with CaG compared to the PG as stimulants. In the present study we noticed a trend of basic and post-stimulation concentrations of PCT to increase in the tests with PG and CaG which correspond with the elevated concentrations of CT.


Subject(s)
Biomarkers, Tumor/analysis , Calcitonin/blood , Calcium Gluconate/pharmacology , Carcinoma, Medullary/surgery , Pentagastrin/pharmacology , Adult , Aged , Aged, 80 and over , Carcinoma, Medullary/diagnosis , Female , Humans , Male , Middle Aged , Pentagastrin/administration & dosage , Thyroid Gland/surgery , Thyroid Neoplasms/surgery , Thyroidectomy/methods
13.
Rev Esp Med Nucl Imagen Mol ; 34(6): 378-82, 2015.
Article in English, Spanish | MEDLINE | ID: mdl-26420439

ABSTRACT

Many open questions remain to be elucidated about the diagnosis, treatment and prognosis of medullary thyroid cancer (MTC). The most intriguing concerns the outcome of MTC patients after surgery. Great importance is usually given to serum calcitonin (Ct) and carcinoembryonic (CEA) levels. It is commonly believed that the higher are the levels of these tumor markers and their kinetics (double time and velocity of markers levels) the worst is the prognosis. However, this is not the rule, as there are huge MTC metastatic deposits characterized by low serum Ct and CEA levels, and this condition is not closely related to the outcome of the disease during post-surgical follow-up. A series is reported here of patients who have these characteristics, as well as a description of their prognosis and clinical outcome.


Subject(s)
Calcitonin/blood , Carcinoma, Medullary/blood , Carcinoma, Neuroendocrine/blood , Hypercalcemia/etiology , Thyroid Neoplasms/blood , Adenocarcinoma, Follicular/diagnosis , Adenocarcinoma, Follicular/diagnostic imaging , Adenocarcinoma, Follicular/pathology , Aged , Biomarkers, Tumor/blood , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/secondary , Carcinoma, Medullary/diagnostic imaging , Carcinoma, Medullary/genetics , Carcinoma, Medullary/secondary , Carcinoma, Medullary/surgery , Carcinoma, Neuroendocrine/diagnostic imaging , Carcinoma, Neuroendocrine/genetics , Carcinoma, Neuroendocrine/surgery , Carcinoma, Papillary/diagnostic imaging , Delayed Diagnosis , Diagnostic Errors , Female , Humans , Lymph Node Excision , Lymphatic Metastasis , Male , Middle Aged , Multiple Endocrine Neoplasia Type 2a/blood , Multiple Endocrine Neoplasia Type 2a/genetics , Mutation, Missense , Neoplasm Staging/methods , Paraganglioma/diagnostic imaging , Paraganglioma/genetics , Pentagastrin , Proto-Oncogene Proteins c-ret/genetics , Thyroid Neoplasms/diagnostic imaging , Thyroid Neoplasms/genetics , Thyroid Neoplasms/surgery , Thyroidectomy/methods
14.
J Physiol Sci ; 65(6): 545-54, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26319795

ABSTRACT

It is well known that hydrogen sulfide (H2S) protects the gastric mucosa against gastric acid and other noxious stimulants by several mechanisms but until now the effect of gastric acid on H2S production has not been evaluated. This study was performed to determine the effect of basal and stimulated gastric acid secretion on mRNA and protein expression of cystathionine gamma lyase (CSE) and cystathionine beta synthase (CBS), and on mucosal release of H2S in rats. Seventy-two male rats were randomly assigned into 9 groups (8 in each)-control, distention, and pentagastrin-induced gastric acid secretion groups. The effects of 15% alcohol solution, propargylglycine (PAG), L-NAME, and pantoprazole were also investigated. Under anesthesia, animals underwent tracheostomy and midline laparotomy. A catheter was inserted into the stomach through the duodenum for gastric washout. At the end of the experiments, the animals were killed and the gastric mucosa was collected to measure H2S concentration and to quantify mRNA expression of CSE and CBS by quantitative real-time PCR, and expression of their proteins by western blot. Basal and stimulated gastric acid secretion increased mucosal levels of H2S, and mRNA and protein expression of CSE. Pantoprazole and L-NAME reversed H2S release and restored protein expression of CSE to the control level. Pantoprazole, but not propargylglycine, pretreatment inhibited the elevated level of protein expression of eNOS in response to distention-induced gastric acid secretion. Our findings indicated that NO mediated the stimulatory effect of gastric acid on H2S release and protein expression of CSE.


Subject(s)
Cystathionine gamma-Lyase/metabolism , Gastric Acid/physiology , Gene Expression Regulation/physiology , Hydrogen Sulfide/metabolism , RNA, Messenger/metabolism , Up-Regulation/physiology , 2-Pyridinylmethylsulfinylbenzimidazoles/pharmacology , Alcohols/pharmacology , Animals , Anti-Ulcer Agents/pharmacology , Cystathionine beta-Synthase/genetics , Cystathionine beta-Synthase/metabolism , Cystathionine gamma-Lyase/genetics , Gastric Mucosa/metabolism , Gene Expression Regulation, Enzymologic/physiology , Male , Nitric Oxide/metabolism , Nitric Oxide Synthase Type III/metabolism , Pantoprazole , Pentagastrin/pharmacology , RNA, Messenger/genetics , Rats , Rats, Wistar , Real-Time Polymerase Chain Reaction
15.
Tohoku J Exp Med ; 235(3): 249-53, 2015 03.
Article in English | MEDLINE | ID: mdl-25786769

ABSTRACT

Gastroesophageal reflux disease (GERD) is a common disease, in which the reflux of gastric acid causes mucosal damage of the esophagus and/or troublesome symptoms. Esomeprazole, a proton pump inhibitor, has been used for treatment of GERD in Japan since 2011; namely, only little is known about its effect on gastric acid secretion in Japanese. We, therefore, assessed the relationship between dose and timing of esomeprazole administration and gastric acid inhibition in 11 healthy male Japanese volunteers by directly examining gastric acid secretion capacity. In this randomized, open-label, three-way crossover study, the subjects were dosed with esomeprazole 10 mg or 20 mg once a day (q.d.), or 20 mg twice a day (b.i.d.) for 14 days, and pentagastrin-stimulated gastric acid secretion was measured by endoscopic gastrin test. At steady states, gastric acid inhibition rates were significantly higher in esomeprazole 20 mg b.i.d. (median 100.0%, interquartile range [IQR] 99.4-100%, P = 0.027) or 20 mg q.d. (100.0%, IQR 99.7-100%, P = 0.016), compared with 10 mg q.d. (98.4%, IQR 84.4-100%). At trough states, esomeprazole 20 mg b.i.d. showed significantly higher gastric acid inhibition (99.6%, IQR 99.0-100%) than did 20 mg q.d. (84.2%, IQR 76.4-88.8%, P = 0.002) or 10 mg q.d. (64.9%, IQR 59.1-76.7%, P = 0.001). Thus, esomeprazole 20 mg b.i.d. was sufficient to inhibit > 99% gastric acid secretion in healthy subjects. We propose that esomeprazole 20 mg b.i.d. is effective for treating Japanese patients with refractory GERD who require long-lasting gastric acid inhibition.


Subject(s)
Esomeprazole/pharmacology , Gastric Acid/metabolism , Pentagastrin/antagonists & inhibitors , Pentagastrin/pharmacology , Proton Pump Inhibitors/pharmacology , Adult , Aged , Asian People , Cross-Over Studies , Cytochrome P-450 CYP2C19/genetics , Dose-Response Relationship, Drug , Esomeprazole/administration & dosage , Genotype , Helicobacter Infections/metabolism , Helicobacter pylori , Humans , Male , Middle Aged , Proton Pump Inhibitors/administration & dosage , Young Adult
16.
J Pharm Sci ; 104(9): 2887-93, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25720462

ABSTRACT

We attempted to establish animal models to evaluate the effects of drug degradation in the stomach on oral bioavailability. In addition, we assessed the utilization of animal studies in determining the need for enteric-coated formulations. In order to control the gastric pH in rats and dogs, appropriate dosing conditions were investigated using pentagastrin and rabeprazole, which stimulate and inhibit gastric acid secretion. Using animals controlled for gastric acid secretion, the area under curve (AUC) ratios (AUC with rabeprazole/AUC with pentagastrin) of all compounds unstable under acidic conditions were evaluated. The AUC ratios of omeprazole and erythromycin, which are administered orally to humans, as enteric-coated tablets, were greater than 1.9 in the rats and dogs controlled for gastric acid secretion. On the contrary, the AUC ratios of clarithromycin, azithromycin, and etoposide (commercially available as a standard immediate-release form) were less than 1.3 each. In conclusion, in vivo models using rats and dogs were optimized to evaluate the effects of gastric acid on the oral bioavailability of drugs, and demonstrated that in vivo models can lead to a better understanding of the oral bioavailability, with respect to the formulation development.


Subject(s)
Gastric Acid/metabolism , Pharmaceutical Preparations/chemistry , Animals , Area Under Curve , Biological Availability , Chemistry, Pharmaceutical , Dogs , Gastric Acidity Determination , Gastric Emptying , Hydrogen-Ion Concentration , Male , Pentagastrin/pharmacology , Proton Pump Inhibitors/pharmacology , Rats , Tablets, Enteric-Coated
17.
World J Gastroenterol ; 20(35): 12542-50, 2014 Sep 21.
Article in English | MEDLINE | ID: mdl-25253956

ABSTRACT

AIM: To explore the role and mechanisms of extracellular signal-regulated protein kinase-mitogen-activated protein kinase (ERK-MAPK) signaling in pentagastrin-regulated growth of large intestinal carcinoma. METHODS: HT-29 cells were incubated in different media and divided into the control group, pentagastrin group, proglumide group, and pentagastrin + proglumide group. No reagent was added to the control group, and other groups were incubated with reagent at different concentrations. Changes in proliferation of HT-29 cells were detected by MTT assay, and the optimal concentrations of pentagastrin and proglumide were determined. The changes in proliferation index (PI) and apoptosis rate (AR) of HT-29 cells were detected by Annexin V-fluorescein isothiocyanate flow cytometry. mRNA expression of pentagastrin receptor/cholecystokinin-B receptor (CCK-BR), ERK1/2 and K-ras were detected by reverse transcriptase polymerase chain reaction. The protein and phosphorylation level of ERK1/2 and K-ras were detected by western blotting. All data were analyzed by analysis of variance and SNK-q test. RESULTS: The proliferation of HT-29 cells was stimulated by pentagastrin at a concentration of 6.25-100 mg/L, and the optimal concentration of pentagastrin was 25.0 mg/L (F = 31.36, P < 0.05). Proglumide had no obvious effect on the proliferation of HT-29 cells, while it significantly inhibited the proliferation of HT-29 cells stimulated by pentagastrin when the concentration of proglumide was 8.0-128.0 mg/L, and the optimal concentration was 32.0 mg/L (F = 24.31, P < 0.05). The PI of the pentagastrin (25.0 mg/L) group was 37.5% ± 5.2%, which was significantly higher than 27.7% ± 5.0% of the control group and 27.3% ± 5.8% of the pentagastrin (25.0 mg/L) + proglumide (32.0 mg/L) group (Q = 4.56-4.75, P < 0.05). The AR of the pentagastrin (25.0 mg/L) group was 1.9% ± 0.4%, which was significantly lower than 2.5% ± 0.4% of the control group and 2.4% ± 0.3% of the pentagastrin (25.0 mg/L) + proglumide (32.0 mg/L) group (Q = 4.23-4.06, P < 0.05). mRNA expression of CCK-BR was detected in HT-29 cells. The phosphorylation levels of ERK1/2 protein and phosphorylated K-ras protein of the pentagastrin group were 0.43% ± 0.04% and 0.45% ± 0.06%, which were significantly higher than 0.32% ± 0.02% and 0.31% ± 0.05% of the control group (Q = 7.78-4.95, P < 0.05), and 0.36% ± 0.01% and 0.35% ± 0.04% of the pentagastrin + proglumide group (Q = 5.72-4.08, P < 0.05). There were no significant differences in the mRNA and protein expression of ERK1/2 and K-ras among the control, pentagastrin, proglumide and pentagastrin + proglumide groups (F = 0.52, 0.72, 0.78, 0.28; P > 0.05). CONCLUSION: Gastrin stimulates proliferation of HT-29 cells and inhibits apoptosis by upregulating phosphorylation of ERK and K-ras through the Ras-Raf-MEK1/2-ERK1/2 pathway, and this is restrained by proglumide.


Subject(s)
Adenocarcinoma/enzymology , Cell Proliferation/drug effects , Colonic Neoplasms/enzymology , MAP Kinase Signaling System/drug effects , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Pentagastrin/pharmacology , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Apoptosis/drug effects , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Dose-Response Relationship, Drug , Enzyme Activation , HT29 Cells , Humans , Mitogen-Activated Protein Kinase 1/genetics , Mitogen-Activated Protein Kinase 3/genetics , Phosphorylation , Proglumide/pharmacology , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins p21(ras) , RNA, Messenger/metabolism , Receptor, Cholecystokinin B/agonists , Receptor, Cholecystokinin B/genetics , Receptor, Cholecystokinin B/metabolism , ras Proteins/genetics , ras Proteins/metabolism
18.
J Clin Endocrinol Metab ; 99(12): 4704-11, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25215555

ABSTRACT

CONTEXT: Elevated calcitonin levels occur in up to 46% of patients with chronic hemodialysis (CHD) and frequently reflect benign C-cell hyperplasia rather than medullary thyroid carcinoma. For the differential diagnosis of hypercalcitoninemia, the pentagastrin-stimulated calcitonin test was used until its availability became restricted. OBJECTIVE: This study sought to compare calcium and pentagastrin in terms of their ability to stimulate calcitonin secretion and their side effects in patients with CHD. SETTING AND DESIGN: This prospective pilot study was conducted at the chronic hemodialysis unit of the Medical University of Vienna between December 2012 and September 2013. PATIENTS: We studied six male patients with CHD with elevated basal calcitonin levels. INTERVENTION: The stimulation test was performed first with 0.5 µg/kg pentagastrin and then with 1 mg/kg calcium after a median washout period of 7 (6-9) months. MAIN OUTCOME MEASURES: We measured calcitonin, serum ionized calcium, intact PTH (iPTH), and C-terminal fibroblast growth factor 23 levels before and 2, 5, and 10 minutes after iv infusion of the stimulant and assessed the tolerability of the two substances by a questionnaire. RESULTS: Both pentagastrin and calcium significantly stimulated calcitonin secretion at 2 and 5 minutes. Partial correlation analysis revealed a strong association between calcium- and pentagastrin-stimulated calcitonin levels (r=0.875, P < .0001). Only after calcium infusion serum ionized calcium levels increased from 1.09 (0.91-1.16) mmol/l to 1.4 (1.14-1.65) mmol/l at 2 minutes (P < .01) but returned to baseline levels at 5 minutes. Moreover, calcium infusion led to a significant decrease in iPTH levels from 315 (203-723) pg/ml to 182 (121-415) pg/ml at 5 minutes (P < .05) and 171 (91-346) pg/ml at 10 minutes (P < .001). In general, calcium caused fewer and less severe side effects than pentagastrin. CONCLUSIONS: In patients with CHD, the response of calcitonin to calcium and pentagastrin was comparable, making calcium a potential substitute for pentagastrin in these patients.


Subject(s)
Calcitonin/biosynthesis , Calcium , Pentagastrin , Renal Dialysis , Renal Insufficiency, Chronic/drug therapy , Renal Insufficiency, Chronic/metabolism , Adult , Aged , Calcitonin/blood , Calcium/administration & dosage , Calcium/blood , Dose-Response Relationship, Drug , Fibroblast Growth Factor-23 , Fibroblast Growth Factors/blood , Humans , Infusions, Intravenous , Male , Middle Aged , Parathyroid Hormone/blood , Pentagastrin/administration & dosage , Pilot Projects
19.
Tohoku J Exp Med ; 232(4): 255-61, 2014 04.
Article in English | MEDLINE | ID: mdl-24670370

ABSTRACT

Gastric acid measurement is useful in assessing the effectiveness of antisecretory drugs, however, the conventional tests involve invasive nasogastric intubation. Orally administered ¹³C-labeled calcium carbonate (Ca¹³CO3) reacts with gastric acid to produce ¹³C-labeled carbon dioxide (¹³CO2), which is then excreted in the breath. The objective of this study was to evaluate the suitability of Ca¹³CO3 breath test for estimating gastric acid secretion in human noninvasively. First, the Ca¹³CO3 breath test and the measurement of pooled gastric acid under a fasting condition were performed in 6 healthy volunteers to evaluate the correlation between the two parameters. Next, endoscopic gastric acid collection and the Ca¹³CO3 breath test were performed on different days after pentagastrin injection in 20 subjects to evaluate the correlation between the tests and the reproducibility. Finally, the same studies were repeated in 4 subjects before and after 1-week rabeprazole, a proton pump inhibitor, administration. The maximum CO2 concentration (Cmax) correlated very well with the amount of pooled gastric acid (r = 0.95), suggesting that Ca¹³CO3 breath test values well reflected the fasting intragastric acidity. The ¹³CO2 concentration after pentagastrin injection correlated well with pentagastrin-stimulated maximal acid output (r = 0.79 at 20 min). The reproducibility of the Ca¹³CO3 breath test under pentagastrin-stimulation was good (coefficient of variation = 0.11). Rabeprazole administration markedly reduced the values of the Ca¹³CO3 breath test, suggesting that it can sensitively assess the efficacy of rabeprazole. The Ca¹³CO3 breath test can potentially be a useful method for non-invasive estimation for gastric acid secretion in human.


Subject(s)
Breath Tests/methods , Gastric Acid/metabolism , Gastric Acidity Determination , Calcium Carbonate/administration & dosage , Calcium Carbonate/metabolism , Carbon Isotopes/administration & dosage , Carbon Isotopes/metabolism , Humans , Linear Models , Pentagastrin/pharmacology , Proton Pump Inhibitors/pharmacology , Rabeprazole/pharmacology , Spectrophotometry, Infrared
20.
Endocrine ; 46(3): 549-53, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24272596

ABSTRACT

The aim of this study was to compare the side effects of the pentagastrin test and the calcium stimulation test in patients with increased basal calcitonin concentration, especially the gender-specific differences of side effects. A total of 256 patients (123 females and 133 males, mean age of 56 ± 27 years, range 21-83 years) had both pentagastrin and calcium stimulation tests. All patients filled in a questionnaire regarding the side effects within 30 min after completion of the stimulation tests. The differences of side effects between female and male patients as well as between the pentagastrin stimulation test and the calcium stimulation test were evaluated. Warmth feeling was the most frequent occurring side effect in all patients who had both pentagastrin and calcium stimulation tests, followed by nausea, altered gustatory sensation, and dizziness. The incidences of urgency to micturate (p < 0.05) and dizziness (p < 0.05) were significantly increased in the female patients as compared to male patients by calcium stimulation test. Significant higher incidences of urgency to micturate (p < 0.05) and warmth feeling (p < 0.05) were found by calcium stimulation test as compared with those by pentagastrin test in female patients. The incidences of nausea (p < 0.05) and abdominal cramping (p < 0.05) in male patients were significantly higher by pentagastrin stimulation test than by calcium stimulation test. There is a significant gender-specific difference in side effects induced by calcium stimulation test. Female patients have fewer side effects by pentagastrin test than by calcium stimulation test. Male patients may tolerate the calcium stimulation test better than the pentagastrin test.


Subject(s)
Calcitonin/blood , Calcium Gluconate/adverse effects , Carcinoma, Medullary/diagnosis , Pentagastrin/adverse effects , Thyroid Function Tests/adverse effects , Thyroid Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Carcinoma, Medullary/blood , Female , Humans , Male , Middle Aged , Sex Factors , Surveys and Questionnaires , Thyroid Neoplasms/blood , Young Adult
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