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1.
Dig Dis ; 41(2): 198-205, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36423587

RESUMO

BACKGROUND: Chronic atrophic gastritis (CAG) alone is a precancerous condition for gastric cancer. Achlorhydria plays an important role in the formation of a class I carcinogen, acetaldehyde. L-cysteine has been claimed to bind acetaldehyde covalently. Symptoms are present in 55% of CAG patients, of whom 70% have upper gastrointestinal complaints. The aim of this study was to investigate the properties of L-cysteine in the modification of symptom patterns in CAG patients. METHODS: Consecutive patients with histological diagnosis of CAG (OLGA ≥1 with gastric corpus involvement) were evaluated with serological determination of gastric function, clinical assessment of symptoms using the visual analog score (VAS) and the global symptomatic score (GSS), and considered for therapy with L-cysteine, 300 mg daily. Data regarding symptoms were collected at enrollment and after 3, 6, 12, 18, and 24 months, with an ultimate follow-up of 2 years. RESULTS: A total of 330 patients with CAG were divided in group 1 (77 patients treated with L-cysteine) and group 2 (50 patients who received no specific treatment - control group). A statistically significant improvement in the VAS score (7.8 at baseline vs. 4.5 after 24 months; p < 0.01) was observed in patients treated with L-cysteine, while no significant changes in symptom pattern/intensity were recorded in the 2-year follow-up of untreated patients with CAG. CONCLUSIONS: Long-term treatment with L-cysteine provides symptom improvement in CAG patients and might be proposed as maintenance therapy in such patients.


Assuntos
Gastrite Atrófica , Helicobacter pylori , Neoplasias Gástricas , Humanos , Gastrite Atrófica/tratamento farmacológico , Cisteína/uso terapêutico , Cisteína/metabolismo , Neoplasias Gástricas/patologia , Acetaldeído/metabolismo , Mucosa Gástrica/patologia
2.
Helicobacter ; 27(2): e12872, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34997989

RESUMO

BACKGROUND AND AIM: In the gastric mucosa, pepsinogen II (PgII) is produced/secreted by glands in the mucus-secreting antral and cardia compartments, but also by the chief cells and the oxyntic glands. Increasing PgII serum levels are associated with the whole spectrum of gastric inflammatory diseases, including gastritis induced by Helicobacter pylori (H. pylori). This review critically addresses the clinical value of PgII serology for assessing gastric mucosal inflammation, and as a marker of H. pylori status, in both H. pylori-positive patients and after eradication therapy. RESULTS: A search in PubMed/Scopus records yielded 39 out of 1190 published scientific studies meeting the selection criteria for this study. In the studies considered, PgII levels were significantly associated with non-atrophic gastric inflammatory lesions (p-values: 0.025-0.0001). H. pylori-positive patients had significantly higher PgII levels than H. pylori-negative individuals (p-values: 0.o5-0.0001). While a significant drop in serum PgII levels is consistently reported in H. pylori-eradicated patients (p-values: from 0.05 to 0.0001), inconsistencies in the related negative and positive predictive values significantly lower the clinical reliability of PgII testing by comparison with other available non-invasive tests. CONCLUSIONS: PgII serology may provide clinically useful information on gastric inflammatory diseases, particularly if they are non-atrophic. PgII serology is inconsistent, however, for the purposes of distinguishing patients whose H. pylori eradication therapy is successful from those who remain infected.


Assuntos
Gastrite Atrófica , Gastrite , Infecções por Helicobacter , Helicobacter pylori , Mucosa Gástrica/patologia , Gastrite/patologia , Gastrite Atrófica/patologia , Infecções por Helicobacter/complicações , Humanos , Pepsinogênio A , Pepsinogênio C , Reprodutibilidade dos Testes
4.
Adv Clin Exp Med ; 32(9): 1075-1080, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37665080

RESUMO

BACKGROUND: Proton pump inhibitors (PPIs) are currently the reference drugs for gastroesophageal reflux disease (GERD), but symptoms often recur after their withdrawal. Moreover, whether prokinetics or barrier drugs used alongside PPIs are more effective remains under debate. OBJECTIVES: The aim of the study was to assess the efficacy of different therapeutic approaches to GERD treatment. MATERIAL AND METHODS: We enrolled 211 grade A reflux esophagitis patients who consented to participate in this non-randomized, open-label trial. The study consisted of 6 sequentially administered medical treatments for GERD, lasting 2 months, with a 3-week washout period between each drug schedule: Group A: PPI (esomeprazole 40 mg/day before breakfast); Group B: mucosal protective drugs (a combination of hyaluronic acid, chondroitin sulfate and poloxamer 407, or a combination of hyaluronic acid, chondroitin sulfate and aluminum, 3 times daily after a meal); Group C: prokinetics (levosulpiride 25 mg or domperidone 10 mg, 3 times daily before a meal); Group D: barrier drug (alginate 3 times daily after a meal); Group E: PPI (esomeprazole 40 mg/day before breakfast) and mucosal protective drugs (a combination of hyaluronic acid, chondroitin sulfate and poloxamer 407, or a combination of hyaluronic acid, chondroitin sulfate and aluminum, before sleep); Group F: PPI (esomeprazole 40 mg/day before breakfast) and prokinetics (levosulpiride 25 mg or domperidone 10 mg before lunch and dinner). Symptoms were evaluated using the visual analogue scale (VAS) and global symptomatic score (GSS), as follows: heartburn: 0-3; retrosternal chest pain: 0-3; regurgitation: 0-3. RESULTS: All but 2 treatments (groups C and D) significantly improved VAS and GSS, with group E showing the most significant GSS improvement. Group C had the highest number of dropouts due to treatment failure and reported more side effects. CONCLUSION: Using PPIs and mucosal protective drugs resulted in significant symptom alleviation. However, the administration of prokinetics caused higher dropouts due to treatment failure.

5.
Acta Biomed ; 94(3): e2023096, 2023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37326271

RESUMO

Hydrochloric acid is crucial in gastric physiology. In 1978 cimetidine, the first H2 antagonist of histamine receptors on the gastric parietal cell was introduced into therapy, inducing acid. Lasting the years, several studies focused on the potential relationship between inducing hypo-achlorhydria and risk of developing gastric cancer. In 1988 omeprazole, the first proton pump inhibitor, entered therapy. In 1996, Kuipers underlined the danger of progression of chronic atrophic gastritis in subjects taking PPIs. In 2018, one paper from Korea and an another on from Sweden suggested a possible relationship between long-term PPI therapy and the development of gastric cancer. Over the years, several articles, meta-analyzes and population based  focused on relationship between long-term of PPI use and the onset of gastric cancer, with conflicting results. As reported, the presence of bias in the collection of cases, in particular concerning the evaluation of the H.p. status and presence of atrophic gastritis and intestinal metaplasia in subjects treated with PPI, can lead to noticeable errors in the results and conclusions, as demonstrated in the literature by exhaustive methodological studies of pharmacoepidemiology. A possible bias in the collection of case histories is due to the fact that PPIs are often administered to dyspeptic patients, among which there are patients already carriers of gastric neoplasia: the so-called inverse causality.  Literature data, amended by methodological bias (sampling errors, lack of comparative assessment of Hp status and atrophic gastritis) NOT support a causal relationship between long-term PPIs therapy and the onset of gastric cancer.


Assuntos
Gastrite Atrófica , Neoplasias Gástricas , Humanos , Gastrite Atrófica/induzido quimicamente , Gastrite Atrófica/complicações , Neoplasias Gástricas/etiologia , Inibidores da Bomba de Prótons/efeitos adversos , Omeprazol/efeitos adversos , Causalidade
6.
J Gastrointestin Liver Dis ; 31(2): 223-228, 2022 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-35574619

RESUMO

Burning mouth syndrome (BMS) is defined as "idiopathic orofacial pain with intraoral burning or dysesthesia recurring daily for more than 2 hours per day and more than 3 months, without any identifiable causative lesions, with or without somatosensory changes" in International Classification of Orofacial Pain, 2020. Worldwide prevalence of BMS was estimated to be 1.73% in population-based studies, while female and elderly are at higher risk of BMS. The aim of this narrative review is to clarify the main etiopathogenetic factors of BMS investigated so far in the scientific literature. There is growing evidence of an important role of peripheral neuropathology in BMS, supported by immunohistochemical studies which have demonstrated a significant loss of epithelial and subepithelial nerve fibers. Other possible etiopathogenetic factors emerging from literature are laryngopharyngeal reflux and hormonal and salivary changes related to aging and menopause. Finally, the role of the oral microbiota in BMS has not yet been thoroughly investigated. Further studies are necessary to investigate the probably multifactorial etiopathogenesis of primary BMS, a pathology which has a serious impact on the quality of life of our patients, a disease we find ourselves treating without the adequate therapy and the necessary knowledge.


Assuntos
Síndrome da Ardência Bucal , Idoso , Síndrome da Ardência Bucal/diagnóstico , Síndrome da Ardência Bucal/epidemiologia , Síndrome da Ardência Bucal/etiologia , Dor Facial/complicações , Feminino , Humanos , Qualidade de Vida
7.
Acta Biomed ; 93(3): e2022184, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35775759

RESUMO

BACKGROUND AND AIM: Chronic Atrophic Gastritis (CAG) is a precancerous condition for gastric cancer (GC) as single risk factor, being a consequence of a previous Helicobacter pylori (Hp) infection or based on autoimmune mechanisms. Achlorhydria plays an important role towards the formation of a class I carcinogen, acetaldehyde, after food intake. L-cysteine has been claimed to be able to bind in a covalent way acetaldehyde when administered at means. METHODS: In this study we enrolled two CAG groups of patients, one treated whit 300 mg/daily of L-cysteine for one year, the other one untreated. We assessed gastric function lasting the one year follow-up by using non invasive surrogates, i.e. Pepsinogen I (PGI) and gastrin 17 (G17). RESULTS: In the group of 77 CAG on therapy we found a statistically significative increase in PGI values and a decrease in G17 levels, in comparison with unchanged values in control group. CONCLUSIONS: L-cysteine seems able to provide a recovery in gastric function when administered in CAG patients and could be proposed as a possible therapy in such patients.


Assuntos
Gastrite Atrófica , Infecções por Helicobacter , Helicobacter pylori , Acetaldeído , Grupos Controle , Cisteína/uso terapêutico , Gastrite Atrófica/tratamento farmacológico , Infecções por Helicobacter/tratamento farmacológico , Humanos , Pepsinogênio A
8.
Acta Biomed ; 93(6): e2022329, 2022 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-36533761

RESUMO

BACKGROUND AND AIM: An association between reflux and burning mouth syndrome (BMS) has been proposed. Aims of this study were: 1) to investigate the frequency of BMS in a sample of GERD patients; 2) to measure G17, in a sample of BMS patients; 3) to assess the efficacy of different therapeutical schedules for GERD in BMS patients. METHODS: We divided the study in 3 main steps. In step one, we analyzed 500 consecutive GERD patients' type and frequency of extraesophageal manifestations including BMS. In step two, we collected 124 consecutive BMS patients' symptoms and  G17.  In step three, we evaluate the efficacy of 3 different drugs on BMS. RESULTS: In step one, 204 patients complained heartburn; 31 globus pharyngeus; 52 chronic cough; 54 pharyngitis; 31 postnasal drip; 56 burning mouth symptoms; 34 noncardiac chest pain; 17 asthma and 21 sleep apnea. In step two, 29 patients had G17 ≤ 1 pg/L; 64 patients between 1 and 3; and 31 patients ≥ 3. In step three, 49 patients reported slight benefit with PPI, 75 no benefit. 61 patients reported slight benefit with sodium alginate and sodium bicarbonate, 63 no benefit. 23 reported an almost complete remission with HYCHSA, 26 slight benefit, 33 no benefit. CONCLUSIONS: Prevalence of BMS in GERD patients was similar to that reported for chronic chough and pharyngitis. Low levels of G17 were found in the majority of BMS patients. Finally, we observed a greater benefit from barrier drugs therapy than from PPI therapy in BMS patients. (www.actabiomedica.it).


Assuntos
Síndrome da Ardência Bucal , Refluxo Gastroesofágico , Faringite , Humanos , Síndrome da Ardência Bucal/epidemiologia , Síndrome da Ardência Bucal/etiologia , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/tratamento farmacológico , Refluxo Gastroesofágico/epidemiologia , Tosse , Dor no Peito , Faringite/complicações
9.
Acta Biomed ; 93(1): e2022130, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35315405

RESUMO

BACKGROUND AND AIM: Barrett's Esophagus represents a condition that predisposes to the development of esophageal adenocarcinoma. The aim of the present study was to analyze the demographic and clinical characteristics of patients with BE, to establish the presence of risk factors for this condition, and to determine the frequency of dysplastic lesions as well as the evolution towards adenocarcinoma under tight endoscopic control. METHODS: In this study, we retrospectively collected and analyzed data from a cohort of patients with Barrett's Esophagus identified through endoscopic records of ULSS7 in Northern Italy, who underwent upper esophagogastroduodenoscopy over a 10-year period from July 2008 to December 2020. RESULTS: A total of 264 patients were identified as having BE and included in the study. Mean follow-up was 6.7 years (range: 3 months-13 years). Demographic characteristics of the study population included mean age of 62.7 years (range 33-90 years), with 62.5% of the study population being aged 60 or older, and a male predominance. Females were significantly older than males (65.7 years, range 37-90 vs 61.9 years, range 33-87, p=0.043, respectively). CONCLUSIONS: The present study confirms the importance of tight endoscopic control in the management of BE, favoring early detection of BE degeneration towards high-grade dysplasia or adenocarcinoma. In a subset of patients with high-risk factors including male sex, cigarette smoking and heavy alcohol intake, it may be worthwhile to consider endoscopic control over time in order to detect the development of BE.


Assuntos
Adenocarcinoma , Esôfago de Barrett , Neoplasias Esofágicas , Adenocarcinoma/epidemiologia , Adenocarcinoma/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Esôfago de Barrett/diagnóstico , Esôfago de Barrett/epidemiologia , Esôfago de Barrett/patologia , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/etiologia , Esofagoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
10.
Acta Biomed ; 93(4): e2022210, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-36043968

RESUMO

Background and aim Increasing the appropriateness of upper gastrointestinal endoscopy (UGIE) improves the quality of care while containing costs. The aim of this study was to improve the appropriateness of UGIE through a process involving evaluation of prescriptions and the use of a non-invasive alternative. Materials and methods A senior endoscopist evaluated the appropriateness of all outpatient referrals for UGIE and established the proper timing. Referrals were either accepted and programmed, canceled, or substituted by a non-invasive evaluation of gastric function, determining serum levels of gastrin-17 (G17), Pepsinogen I (PGI) and II (PGII), and antibodies against Helicobacter pylori. Results A total of 5102 requests for UGIE examinations were evaluated; 540 (10.4%) were inappropriate and had been prescribed for: gastroesophageal reflux disease (n=307), surveillance with erroneous timing (n=113), dyspepsia (n=66), other indications (n=20), and absence of written indication (n=34). Gastric function was evaluated in 282/540 patients; findings included normal values in 94 patients without proton-pump inhibitor therapy (PPI) and in 48 on PPI, active H pylori infection in 56, previous H pylori infection in 30, GERD in n=50, and atrophic gastritis in n=4. UGIE was performed in the latter 4 cases.  Within 2 years (range 1-22 months) of the initial refusal, 105/504 patients underwent UGIE, with normal endoscopic findings in 71/105 (67.5%), and with no cases of cancer. Conclusions This strategy, based on a strict control of prescriptions, is effective to increase the appropriateness while containing public health costs. The use of gastric function testing improves patient selection for UGIE endoscopy.


Assuntos
Endoscopia Gastrointestinal , Helicobacter pylori , Endoscopia Gastrointestinal/métodos , Gastrite Atrófica/diagnóstico por imagem , Refluxo Gastroesofágico/diagnóstico por imagem , Infecções por Helicobacter/diagnóstico por imagem , Humanos , Pepsinogênio A
11.
Acta Biomed ; 92(3): e2021207, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34212902

RESUMO

BACKGROUND AND AIM: We describe a case of Ménétrier disease, occurred in female patient. METHODS: We decide to assess by non-invasive way (serum pepsinogens and gastrin 17) the secretory status of gastric mucosa, to confirm previous data of the literature, claiming high levels of both acid secretion and hypergastrinemia in this rare pathological condition. RESULTS AND CONCLUSION: We find in the subject the highest values of pepsinogen 1 - a marker of acid secretion - never described in the literature to our knowledge: 1940 mcg/L, being normal values ranging from 30-160 mcg/L. Similarly, gastrin 17, produced 90% in the antrum and responsible for negative acid feedback, was very high: 139 pg/L, ranging normal values between 1-10 pg/L. (www.actabiomedica.it).


Assuntos
Gastrite Hipertrófica , Pepsinogênio A , Feminino , Mucosa Gástrica , Gastrinas , Humanos
12.
J Gastrointestin Liver Dis ; 30(1): 25-29, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33548125

RESUMO

BACKGROUND AND AIMS: In clinical practice, most patients with symptoms suggestive of gastroesophageal reflux disease (GERD) undergo esophago-gastro-duodenoscopy (EGD), despite its low sensitivity in detecting reflux stigmata. Gastrin 17 (G-17) has been proposed to be related with GERD, due to the negative feedback between acid secretion and this hormone. We assessed the clinical usefulness of fasting G-17 serum determination for a non-invasive diagnosis of GERD in patients with typical symptoms. METHODS: We consecutively enrolled patients complaining of typical GERD symptoms in two different settings: a single referral center and a primary care setting. Control groups consisted of dyspeptic patients. All subjects underwent assessment of serum levels of G-17 and EGD. RESULTS: At the academic hospital, 100 GERD patients (n=89 with erosive esophagitis and 11 with Barrett's esophagus) had statistically significant low levels of G-17 as compared with 184 dyspeptic patients (1.7±1.2 pg/L vs 8.9±5.7 pg/L p<0.0001). Similarly, in the primary care setting, 163 GERD patients had statistically significant low levels of G-17 as compared with 132 dyspeptic patients (0.5±0.2 pg/L vs. 4.0±2.6 pg/L, p<0.0001). Moreover, in the primary care setting, no statistically significant differences were found for G-17 levels between patients with erosive and non-erosive reflux pattern (0.4±0.2 vs 0.7±0.3; p=0.08). In primary care, the accuracy of G-17 less than 1 pg/L to diagnose non-invasively GERD was 94.3%. CONCLUSIONS: Low levels of G-17 were detected in patients with erosive esophagitis and Barrett's esophagus in a referral center and in patients with typical GERD symptoms in a sample of patients from a primary care setting.


Assuntos
Esofagite Péptica/sangue , Esofagite Péptica/patologia , Esofagoscopia , Gastrinas/sangue , Refluxo Gastroesofágico/sangue , Refluxo Gastroesofágico/patologia , Adulto , Idoso , Esofagite Péptica/complicações , Feminino , Refluxo Gastroesofágico/complicações , Humanos , Masculino , Pessoa de Meia-Idade
13.
J Lipid Res ; 51(6): 1332-43, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19965581

RESUMO

The main retinol carriers in the cytosol are the cellular retinol-binding proteins types I and II (CRBP-I and CRBP-II), which exhibit distinct tissue distributions. They play different roles in the maintenance of vitamin A homeostasis and feature a 100-fold difference in retinol affinity whose origin has not been described in detail. NMR-based hydrogen/deuterium exchange measurements show that, while retinol binding endows both proteins with a more rigid structure, many amide protons exchange much faster in CRBP-II than in CRBP-I in both apo and holo form, despite the conserved three-dimensional fold. The remarkable difference in intrinsic stability between the two homologs appears to modulate their binding properties: the stronger retinol binder CRBP-I displays a reduced flexibility of the backbone structure with respect to CRBP-II. This difference must derive from specific evolution-based amino acid substitutions, resulting in additional stabilization of the CRBP-I scaffold: in fact, we identified a number of potential salt bridges on the protein surface as well as several key interactions inside the binding cavity. Furthermore, our NMR data demonstrate that helix alphaII of the characteristic helix-turn-helix motif in the ligand portal region exists in both apo and holo CRBP-II. Hence, the previously proposed model of retinol binding needs to be revised.


Assuntos
Proteínas Celulares de Ligação ao Retinol/metabolismo , Vitamina A/metabolismo , Sequência de Aminoácidos , Animais , Apoproteínas/química , Apoproteínas/metabolismo , Medição da Troca de Deutério , Evolução Molecular , Humanos , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Ligação Proteica , Estabilidade Proteica , Estrutura Secundária de Proteína , Ratos , Proteínas Celulares de Ligação ao Retinol/química , Alinhamento de Sequência
14.
Acta Biomed ; 91(3): e2020069, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32921764

RESUMO

Dyspepsia is a functional GI disorder consisting in a wide range of symptoms. The main diagnostic challenge has been whether to perform an EGD or an abdominal US in order not to miss organic lesions, but to avoid unnecessary and sometimes invasive tests. Pepsinogen serology has been proposed as an useful non-invasive test to explore the status of the gastric mucosa, suggesting this strategy as an adequate approach in management of dyspepsia. In a primary care setting, 266 dyspeptic patients were investigated to establish the proper diagnosis. The workup included upper GI endoscopy with biopsies, a structured questionnaire including type and severity of symptoms, serological determination of serum pepsinogens, gastrin 17 and IgG against Hp. Inclusion criteria were dyspeptic symptoms (epigastric pain, nausea and/or vomiting, post prandial fullness, early satiation) lasting more than 1 year and the association between symptoms and food ingestion.. Helicobacter pylori infection was present in 114 subjects, characterized by high levels of pepsinogen II and IgG against Hp. Twenty subjects were classified according with the diagnosis of chronic body atrophic gastritis. Nausea and post prandial fullness were the most frequent symptoms (48% and 41%, respectively) in the studied population, followed by epigastric pain and early satiation (37% and 26% respectively). A diagnosis of normality by serological diagnosis was found in half of patients experiencing epigastric pain and in about 60% of subjects with the three other symptoms (nausea, post prandial fullness, and early satiation). In conclusion, this experience confirms the clinical usefulness of serology in dyspepsia, contributing to correctly diagnosing CAG and H.p. infection in such patients and providing a good correlation with the clinical picture.


Assuntos
Dispepsia/diagnóstico , Adulto , Idoso , Dispepsia/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Amino Acids ; 36(4): 633-41, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18696179

RESUMO

Activation of tissue transglutaminase by calcium involves a conformational change which allows exposition of the active site to the substrate via movements of domains 3 and 4 that lead to an increase of the inter-domain distance. The inhibitor GTP counteracts these changes. Here we investigate the possible existence of non-native conformational states still compatible with the enzyme activity produced by chemical and thermal perturbations. The results indicate that chemical denaturation is reversible at low guanidine concentrations but irreversible at high concentrations of guanidine. Indeed, at low guanidine concentrations tissue TG-ase exists in a non-native state which is still affected by the ligands as in the native form. In contrast, thermal unfolding is always irreversible, with aggregation and protein self-crosslinkage in the presence of calcium. DSC thermograms of the native protein in the absence of ligands consist of two partly overlapped transitions, which weaken in the presence of calcium and merge together and strengthen in the presence of GTP. Overall, the present work shows, for the first time, the reversible denaturation of a TG-ase isoenzyme and suggests the possibility that also in in vivo, the enzyme may acquire non-native conformations relevant to its patho-physiological functions.


Assuntos
Proteínas de Ligação ao GTP/metabolismo , Dobramento de Proteína , Transglutaminases/metabolismo , Cálcio/química , Cálcio/metabolismo , Proteínas de Ligação ao GTP/antagonistas & inibidores , Proteínas de Ligação ao GTP/química , Guanidina/farmacologia , Temperatura Alta , Isoenzimas/antagonistas & inibidores , Isoenzimas/química , Isoenzimas/metabolismo , Desnaturação Proteica , Proteína 2 Glutamina gama-Glutamiltransferase , Fatores de Tempo , Transglutaminases/antagonistas & inibidores , Transglutaminases/química
16.
J Phys Chem Lett ; 10(23): 7333-7339, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31714784

RESUMO

Due to the poor aqueous solubility of retinoids, evolution has tuned their binding to cellular proteins to address specialized physiological roles by modulating uptake, storage, and delivery to specific targets. With the aim to disentangle the structure-function relationships in these proteins and disclose clues for engineering selective carriers, the binding mechanism of the two most abundant retinol-binding isoforms was explored by using enhanced sampling molecular dynamics simulations and surface plasmon resonance. The distinctive dynamics of the entry portal site in the holo species was crucial to modulate retinol dissociation. Remarkably, this process is controlled to a large extent by the replacement of Ile by Leu in the two isoforms, thus suggesting that fine control of ligand release can be achieved through a rigorous selection of conservative mutations in accessory sites.


Assuntos
Proteínas Celulares de Ligação ao Retinol/metabolismo , Vitamina A/metabolismo , Sítios de Ligação , Humanos , Isomerismo , Cinética , Ligantes , Simulação de Dinâmica Molecular , Ligação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Proteínas Celulares de Ligação ao Retinol/química , Termodinâmica , Vitamina A/química
17.
Acta Biomed ; 89(8-S): 40-43, 2018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30561416

RESUMO

Gastroesophageal reflux disease (GERD) is due to the chronic exposure of the esophageal mucosa to acid secretion from the stomach. Helicobacter pylori (H.p.) infection, is a risk factor for the development of peptic ulcer, atrophic gastritis and gastric cancer, and causes various effects on gastric function. The relationship between GERD and H.pylori infection is still subject of debate. Background and aim: In literature no clear causal relationship has been established between GERD and H. pylori infection, although some papers support the onset of esophagitis in patients in whom the infection has been cured. Aim of this work is to review the most recent literature data about the relationship between reflux disease and H. pylori infection. Methods: Articles reviewed were found through literature searches on PubMed, Google Scholar using keywords such as gastroesophageal reflux disease, Helicobacter pylori, acid-related disorders, GERD and esophagitis.


Assuntos
Gastrite/complicações , Refluxo Gastroesofágico/complicações , Infecções por Helicobacter/complicações , Helicobacter pylori/patogenicidade , Antibacterianos/uso terapêutico , Causalidade , Esofagite Péptica/etiologia , Gastrite/tratamento farmacológico , Gastrite/microbiologia , Refluxo Gastroesofágico/fisiopatologia , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/isolamento & purificação , Humanos , Úlcera Péptica/epidemiologia , Úlcera Péptica/etiologia , Úlcera Péptica/prevenção & controle , Fumar/efeitos adversos , Neoplasias Gástricas/etiologia , Neoplasias Gástricas/prevenção & controle
18.
Acta Biomed ; 89(8-S): 53-57, 2018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30561418

RESUMO

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.


Assuntos
Acloridria/diagnóstico , Determinação da Acidez Gástrica , Gastrinas/sangue , Pepsinogênios/sangue , Acloridria/sangue , Acloridria/fisiopatologia , Biomarcadores , Ácido Gástrico/metabolismo , Gastrite Atrófica/sangue , Gastrite Atrófica/diagnóstico , Gastrite Atrófica/fisiopatologia , Humanos , Pentagastrina/farmacologia , Úlcera Péptica/fisiopatologia , Lesões Pré-Cancerosas/sangue , Lesões Pré-Cancerosas/diagnóstico , Lesões Pré-Cancerosas/fisiopatologia
19.
Protein Sci ; 14(4): 1025-38, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15772309

RESUMO

Potassium channels are widespread in living cells and are involved in many diseases. The scorpion toxin alpha-KTx(12.1) interacts with various K(+) channels, suggesting its capacity to match diverse channel pores. It is recognized that tissue injuries may affect the pH at toxins site of action, thereby modulating both protein conformation and activity. To better understand its molecular mechanism of action, we studied alpha-KTx(12.1) using pH as a tool to explore its plasticity and NMR in combination with MD calculations to detect it. The toxin solution structure consists of an alpha-helix and a triple-stranded beta-sheet stabilized by four disulfide bridges. The NMR results show, in addition, that His28 possesses an unusually low pK(a) of 5.2. The best set of protein conformers is obtained at pH 4.5, while at pH 7.0, the reduced number of NOEs resulting from a faster hydrogen exchange does not allow to reach a good structural convergence. Nonetheless, MD calculations show that the toxin structure does not vary significantly in that pH range, while conformational changes and modifications of the surface charge distribution occur when His28 is fully protonated. Moreover, essential dynamics analysis reveals variations in the toxin's coherent motions. In conclusion, His28, with its low pK(a) value, provides alpha-KTx(12.1) with the ability to preserve its active conformation over a wide pH interval, thus expanding the range of cellular conditions where the toxin can fully exhibit its activity. Overall, the results further underline the role of histidine as a natural controller of proteins' functionality.


Assuntos
Bloqueadores dos Canais de Potássio/química , Venenos de Escorpião/química , Sequência de Aminoácidos , Simulação por Computador , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Modelos Moleculares , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Bloqueadores dos Canais de Potássio/isolamento & purificação
20.
J Med Chem ; 46(12): 2325-33, 2003 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-12773037

RESUMO

Fibroblast growth factors (FGFs) are regulatory proteins associated with a number of physiological and pathological states. On the basis of data suggesting a functional role for specific regions of human acidic FGF (aFGF), a linear peptide encompassing residues 99-108 (peptide1) and its cyclic analogue (peptide 2) were synthesized and their functional and structural features were investigated. While peptide 1 is inactive on Balb/c 3T3 fibroblasts, peptide 2 is mitogenic with ED(50) of approximately 50 microM. Moreover, peptide 1 is not able to inhibit the binding of human aFGF to cellular receptors whereas peptide 2 exhibits significant inhibitory activity. The NMR-derived solution conformers indicated the presence, only in peptide 2, of structural elements that we believe are related to its ability to emulate the biological activity of the native protein. These results suggest that the expression of mitogenic activity in short peptides, besides the presence of specific amino acids, requires the existence of stable structural features. In addition, they indicate that the introduction of chemical restraints in peptides can provide novel possibilities for the development of receptor agonists or antagonists.


Assuntos
Fator 1 de Crescimento de Fibroblastos/química , Fatores de Crescimento de Fibroblastos/síntese química , Mitógenos/síntese química , Oligopeptídeos/síntese química , Fragmentos de Peptídeos/síntese química , Peptídeos Cíclicos/síntese química , Células 3T3 , Animais , Dicroísmo Circular , Fatores de Crescimento de Fibroblastos/química , Fatores de Crescimento de Fibroblastos/farmacologia , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Mitógenos/química , Mitógenos/farmacologia , Modelos Moleculares , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Conformação Proteica , Timidina/metabolismo
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