RESUMO
BACKGROUND: The severe acute respiratory syndrome Coronarovirus-2 associated still causes a significant number of deaths and hospitalizations mainly by the development of respiratory failure. We aim to validate lung ultrasound score in order to predict mortality and the severity of the clinical course related to the need of respiratory support. METHODS: In this prospective multicenter hospital-based cohort study, all adult patients with diagnosis of SARS-CoV-2 infection, performed by real-time reverse transcription polymerase chain reaction were included. Upon admission, all patients underwent blood gas analysis and lung ultrasound by expert operators. The acquisition of ultrasound scan was performed on 12 peculiar anatomic landmarks of the chest. Lung ultrasound findings were classified according to a scoring method, ranging 0 to 3: Score 0: normal A-lines. Score 1: multiple separated B-lines. Score 2: coalescent B-lines, alteration of pleural line. Score 3: consolidation area. RESULTS: One thousand and seven patients were included in statistical analysis (male 62.4 %, mean age 66.3). Oxygen support was needed in 811 (80.5 %) patients. The median ultrasound score was 24 and the risk of having more invasive respiratory support increased in relation to higher values score computed. Lung ultrasound score showed negative strong correlation (rho: -0.71) with the P/F ratio and a significant association with in-hospital mortality (OR 1.11, 95 %CI 1.07-1.14; p < 0.001), even after adjustment with the following variables (age, sex, P/F ratio, SpO2, lactate, hypertension, chronic renal failure, diabetes, and obesity). CONCLUSIONS: The novelty of this research corroborates and validates the 12-field lung ultrasound score as tool for predicting mortality and severity clinical course in COVID-19 patients. Baseline lung ultrasound score was associated with in-hospital mortality and requirement of intensive respiratory support and predict the risk of IOT among COVID-19 patients.
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Postherpetic neuralgia (PHN) is a chronic neuropathic pain syndrome that is a direct consequence of the reactivation of varicella zoster virus (VZV). It manifests as neuropathic pain, which is pain that occurs because of dysfunction or damage of the nerves that carry sensations to the brain, and this typically persists for months to years after herpes zoster. Current conservative management for PHN includes a combination of topical agents (i.e., lidocaine and capsaicin) and systemic therapy (i.e., serotonin and norepinephrine reuptake inhibitors (SNRIs), gabapentin, pregabalin, and opioids). For refractory cases, with persistent intractable pain, more invasive interventional techniques can be used as pain-relieving measures to improve the patient's quality of life. This report presents a patient with upper limb PHN who responded to peripheral nerve stimulation (PNS) after he failed to obtain sufficient pain relief with conservative management.
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Renal transplantation is the most common solid organ transplant in the United States. Post-transplant neuralgia is a frequent complication and may be due to infection, medication side effects, post-transplant lymphoproliferative disorder (PTLD), or the procedure itself. This case report describes an instance of post-renal transplant neuralgia in a 70-year-old Caucasian female. Diagnostic nerve blocks revealed the involvement of the ilioinguinal, genitofemoral, and lateral femoral cutaneous nerves. The case report details management that included nerve blocks, radiofrequency ablation (RFA), and a permanent peripheral nerve stimulator (PNS) implant.
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BACKGROUND: Excess body fatness and hyperinsulinemia are both associated with an increased risk of postmenopausal breast cancer. However, whether women with high body fatness but normal insulin levels or those with normal body fatness and high levels of insulin are at elevated risk of breast cancer is not known. We investigated the associations of metabolically defined body size and shape phenotypes with the risk of postmenopausal breast cancer in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition. METHODS: Concentrations of C-peptide-a marker for insulin secretion-were measured at inclusion prior to cancer diagnosis in serum from 610 incident postmenopausal breast cancer cases and 1130 matched controls. C-peptide concentrations among the control participants were used to define metabolically healthy (MH; in first tertile) and metabolically unhealthy (MU; >1st tertile) status. We created four metabolic health/body size phenotype categories by combining the metabolic health definitions with normal weight (NW; BMI < 25 kg/m2 , or WC < 80 cm, or WHR < 0.8) and overweight or obese (OW/OB; BMI ≥ 25 kg/m2 , or WC ≥ 80 cm, or WHR ≥ 0.8) status for each of the three anthropometric measures separately: (1) MHNW, (2) MHOW/OB, (3) MUNW, and (4) MUOW/OB. Conditional logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Women classified as MUOW/OB were at higher risk of postmenopausal breast cancer compared to MHNW women considering BMI (OR = 1.58, 95% CI = 1.14-2.19) and WC (OR = 1.51, 95% CI = 1.09-2.08) cut points and there was also a suggestive increased risk for the WHR (OR = 1.29, 95% CI = 0.94-1.77) definition. Conversely, women with the MHOW/OB and MUNW were not at statistically significant elevated risk of postmenopausal breast cancer risk compared to MHNW women. CONCLUSION: These findings suggest that being overweight or obese and metabolically unhealthy raises risk of postmenopausal breast cancer while overweight or obese women with normal insulin levels are not at higher risk. Additional research should consider the combined utility of anthropometric measures with metabolic parameters in predicting breast cancer risk.
Assuntos
Neoplasias , Sobrepeso , Feminino , Humanos , Fatores de Risco , Sobrepeso/complicações , Somatotipos , Pós-Menopausa , Peptídeo C , Estudos de Casos e Controles , Estudos Prospectivos , Obesidade/complicações , Fenótipo , Tamanho Corporal , Índice de Massa CorporalRESUMO
BACKGROUND: Klinefelter syndrome (KS) is frustratingly under-diagnosed. KS have a broad spectrum of clinical features, making it difficult to identify. OBJECTIVE: We describe KS clinical presentation in a large Italian cohort. DESIGN: This is the first observational cohort study within a national network, the Klinefelter ItaliaN Group (KING). Primary outcomes were to describe the basic clinical features and the actual phenotype of KS in Italy. Secondary outcomes were to determine age at diagnosis and geographical distribution. METHODS: We performed a basic phenotyping and evaluation of the hormonal values of 609 adult KS patients. RESULTS: Mean age at diagnosis was 37.4 ± 13.4 years. The overall mean testicular size was 3 ml, and 2.5 ml in both testes in untreated KS group. BMI was 26.6 ± 5.8 kg/m2, and 25.5% of KS had metabolic syndrome (MetS). LH and FSH were increased, and mean total testosterone were 350 ± 9.1 ng/dl. A descriptive analysis showed that 329 KS patients were evaluated in Northern Italy, 76 in Central and 204 in Southern Italy. Analysis of variance demonstrated significant statistical differences (p < 0001) between the age at diagnosis of the three geographical groups. Compared with the expected number among male patients matched for age in Italy, only 16% of KS patients received a diagnosis. CONCLUSIONS: These data are the results of the only national database available that collects the clinical and hormonal data of the KS patients, currently referred at the KING centers. In Italy the typical KS patient is overweight, with small testes, and elevated LH and FSH. Only 25.5% of them are diagnosed with MetS. Early detection and timely treatment are mandatory.
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Hipogonadismo , Síndrome de Klinefelter , Síndrome Metabólica , Hormônio Foliculoestimulante/uso terapêutico , Humanos , Hipogonadismo/tratamento farmacológico , Síndrome de Klinefelter/complicações , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/epidemiologia , Masculino , Síndrome Metabólica/complicações , Síndrome Metabólica/diagnóstico , Síndrome Metabólica/epidemiologia , Testículo , Testosterona/uso terapêuticoRESUMO
The association between early atherosclerosis (IMT) and Atherogenic index of plasma (AIP), a marker of atherogenicity (log triglycerides/HDL Cholesterol) was evaluated in a population-based cohort study in women, aged 30-69, living in the metropolitan area of Naples, Southern Italy (Progetto ATENA). Serum cholesterol, HDL-cholesterol, LDL-cholesterol, Triglyceride, Insulin, HOMA, Apo B, hs-CPR were measured in 390 menopausal women, as a part of 5.062 participants of the cohort. Women in the second and third tertile of AIP showed an increased common carotid intima-media thickness compared with those in the first tertile: II vs I tertile (O.R. = 2.24, p = 0.007), III vs I tertile (O.R. = 2.29, p = 0.005), adjusted for age and Systolic pressure or II vs I tertile (O.R. = 2.19, p = 0.014), III vs I tertile (O.R. = 2.13, p = 0.026), adjusted for age, Systolic pressure, Body mass index and Apo B. Women in the second and third tertile of AIP compared to those in the first tertile, showed an OR of 2.14 (p = 0.016) and 1.99 (p = 0.033) respectively, of having elevates level of IMT, adjusted for traditional cardiovascular risk factor (age, Systolic Pressure, BMI, LDL Cholesterol, Diabetes diagnosis). This finding shows that in this group of menopausal women increased IMT is associated with elevated AIP independently of age and different cardiovascular risk factors. These results are in line with the hypothesis that AIP may be an useful clinical tools to give additional information in the risk assessment for atherosclerotic disease, in particular in postmenopausal women.
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Espessura Intima-Media Carotídea , Índice de Massa Corporal , HDL-Colesterol , Estudos de Coortes , Feminino , Humanos , Fatores de RiscoRESUMO
To understand neutrophil impairment in the progression from MGUS through active MM, we investigated the function of mature, high-density neutrophils (HDNs), isolated from peripheral blood. In 7 MM, 3 MGUS and 3 healthy subjects by gene expression profile, we identified a total of 551 upregulated and 343 downregulated genes in MM-HDN, involved in chemokine signaling pathway and FC-gamma receptor mediated phagocytosis conveying in the activation of STAT proteins. In a series of 60 newly diagnosed MM and 30 MGUS patients, by flow-cytometry we found that HDN from MM, and to a lesser extend MGUS, had an up-regulation of the inducible FcγRI (also known as CD64) and a down-regulation of the constitutive FcγRIIIa (also known as CD16) together with a reduced phagocytic activity and oxidative burst, associated to increased immune-suppression that could be reverted by arginase inhibitors in co-culture with lymphocytes. In 43 consecutive newly-diagnosed MM patients, who received first-line treatment based on bortezomib, thalidomide and dexamethasone, high CD64 could identify at diagnosis patients with inferior median overall survival (39.5 versus 86.7 months, p = 0.04). Thus, HDNs are significantly different among healthy, MGUS and MM subjects. In both MGUS and MM neutrophils may play a role in supporting both the increased susceptibility to infection and the immunological dysfunction that leads to tumor progression.
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Suscetibilidade a Doenças/imunologia , Gamopatia Monoclonal de Significância Indeterminada/imunologia , Mieloma Múltiplo/imunologia , Neutrófilos/imunologia , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/imunologia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Estudos de Casos e Controles , Progressão da Doença , Feminino , Seguimentos , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Gamopatia Monoclonal de Significância Indeterminada/tratamento farmacológico , Gamopatia Monoclonal de Significância Indeterminada/genética , Gamopatia Monoclonal de Significância Indeterminada/mortalidade , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Mieloma Múltiplo/mortalidade , Neutrófilos/metabolismo , Fagocitose/genética , Fagocitose/imunologia , Transdução de Sinais/genética , Evasão Tumoral/genéticaRESUMO
Patients with hepatocellular carcinoma (HCC) comply with an advanced disease and are not eligible for radical therapy. In this distressed scenario new treatment options hold great promise; among them transarterial chemoembolization (TACE) and transarterial metabolic radiotherapy (TAMR) have shown efficacy in terms of both tumor shrinking and survival. External radiation therapy (RTx) by using novel three-dimensional conformal radiotherapy has also been used for HCC patients with encouraging results while its role had been limited in the past for the low tolerance of surrounding healthy liver. The rationale of TAMR derives from the idea of delivering exceptional radiation dose locally to the tumor, with cell killing intent, while preserving normal liver from undue exposition and minimizing systemic irradiation. Since the therapeutic efficacy of TACE is being continuously disputed, the TAMR with (131)I Lipiodol or (90)Y microspheres has gained consideration providing adequate therapeutic responses regardless of few toxicities. The implementation of novel radioisotopes and technological innovations in the field of RTx constitutes an intriguing field of research with important translational aspects. Moreover, the combination of different therapeutic approaches including chemotherapy offers captivating perspectives. We present the role of the radiation-based therapies in hepatocellular carcinoma patients who are not entitled for radical treatment.
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Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/métodos , Quimiorradioterapia/métodos , Neoplasias Hepáticas/terapia , Carcinoma Hepatocelular/patologia , Humanos , Fígado/patologia , Neoplasias Hepáticas/patologiaRESUMO
Tumour cells have long been considered defective in mitochondrial respiration and mostly dependent on glycolytic metabolism. However, this assumption is currently challenged by several lines of evidence in a growing number of tumours. Ovarian cancer (OC) is one of the most lethal cancers worldwide, but it continues to be a poorly understood disease and its metabolic features are far to be elucidated. In this context, we investigated the role of tumour necrosis factor receptor-associated protein 1 (TRAP1), which is found upregulated in several cancer types and is a key modulator of tumour cell metabolism. Surprisingly, we found that TRAP1 expression inversely correlated with grade, stage and lower survival in a large cohort of OC patients. Accordingly, TRAP1 silencing induced resistance to cisplatin, resistant cells showed increased oxidative metabolism compared with their sensitive counterpart, and the bioenergetics cellular index of higher grade tumours indicated increased mitochondrial respiration. Strikingly, cisplatin resistance was reversible upon pharmacological inhibition of mitochondrial oxidative phosphorylation by metformin/oligomycin. At molecular level, increased oxidative metabolism in low TRAP1-expressing OC cells and tissues enhanced production of inflammatory mediators such as interleukin (IL)-6 and IL-8. Mechanistically, we identified members of the multidrug resistance complex (MDR) as key mediators of such metabolism-driven, inflammation-induced process. Indeed, treatment of OC cell lines with TNFα and IL6 induced a selective increase in the expression of TAP1 and multidrug resistance protein 1, whereas TAP1 silencing sensitized cells to cisplatin-induced apoptosis. Our results unveil a novel role for TRAP1 and oxidative metabolism in cancer progression and suggest the targeting of mitochondrial bioenergetics to increase cisplatin efficacy in human OC.
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Cisplatino/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Inflamação/patologia , Neoplasias Ovarianas/tratamento farmacológico , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Intervalo Livre de Doença , Feminino , Glicólise , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/metabolismo , Inflamação/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Interleucina-8/genética , Interleucina-8/metabolismo , Metformina/farmacologia , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Fosforilação Oxidativa/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismoAssuntos
Dexametasona/uso terapêutico , Leucemia Plasmocitária/tratamento farmacológico , Talidomida/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Dexametasona/administração & dosagem , Feminino , Humanos , Lenalidomida , Masculino , Pessoa de Meia-Idade , Talidomida/administração & dosagem , Talidomida/uso terapêuticoRESUMO
Regulatory T cells (Tregs) are considered to be key immunomodulatory cells of the immune system and are increased in chronic lymphocytic leukemia (CLL). Rai stage 0 identifies patients with early stage CLL for which there is no effective intervention at the present time and a "wait and see" policy is usually adopted. Some biological and clinical studies have reported that green tea constituents, such as epigallocatechin-gallate (EGCG), have antitumor effects on hematologic malignancies including CLL. We report data on a clinical trial in which green tea extracts were given orally to 12 patients with stage 0 CLL and 12 healthy subjects. Ten patients and 10 controls completed the 6-month scheduled therapy. Two patients and 2 controls stopped therapy within 1 month because of tachycardia and epigastralgia. Eight out 10 evaluable patients (80 percent) showed a reduction of lymphocytosis and absolute number of circulating Tregs, as well. One patient (10 percent) had a stabilization of lymphocytosis and a reduction of Tregs, and 1 patient (10 percent) showed an increase of both lymphocytosis and Tregs. Only the non-responding patient progressed after 5 months from the end of green tea administration and chemotherapy was given. Interestingly, both IL-10 and TGF-beta serum levels declined throughout the green tea intake period, in both patients and controls. These data seem to indicate that green tea is able to modulate circulating Tregs in CLL patients with early stage of the disease. This can result in the control of lymphocytosis as well as in the prevention of disease progression.
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Camellia sinensis , Fatores Imunológicos/farmacologia , Leucemia Linfocítica Crônica de Células B/imunologia , Extratos Vegetais/farmacologia , Linfócitos T Reguladores/efeitos dos fármacos , Adulto , Idoso , Idoso de 80 Anos ou mais , Contagem de Linfócito CD4 , Cafeína/análise , Catequina/análogos & derivados , Catequina/análise , Feminino , Humanos , Fatores Imunológicos/química , Interleucina-10/sangue , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/química , Linfócitos T Reguladores/imunologia , Fator de Crescimento Transformador beta/sangueRESUMO
The heat inactivation of esterases in human and rabbit serum was followed at 50 and 55 degrees C by measuring the decrease of activity with paraoxon, phenylacetate and beta-naphthylacetate as substrates. The rate of inactivation measured with the three substrates was slightly, but significantly different, indicating that the substrates are hydrolysed by different enzymes.
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Hidrolases de Éster Carboxílico/sangue , Monoéster Fosfórico Hidrolases/sangue , Animais , Arildialquilfosfatase , Interações Medicamentosas , Ativação Enzimática , Estabilidade Enzimática , Temperatura Alta , Humanos , Hidrólise , Cinética , Ácidos Naftalenoacéticos/sangue , Paraoxon/sangue , Fenilacetatos/sangue , CoelhosRESUMO
In patients with hyperlipaemia, serum paraoxonase activities were polymodally distributed with 75% individuals in the low activity mode. In the same patients the distribution of serum cholinesterase activities was unimodal, but asymmetrical. Patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus had slightly higher cholinesterase activities than patients with hyperlipaemia only.
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Colinesterases/sangue , Doenças Metabólicas/enzimologia , Monoéster Fosfórico Hidrolases/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Arildialquilfosfatase , Glicemia/metabolismo , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/enzimologia , Feminino , Teste de Tolerância a Glucose , Humanos , Hiperlipidemias/sangue , Hiperlipidemias/enzimologia , Masculino , Doenças Metabólicas/sangue , Pessoa de Meia-IdadeRESUMO
The hydrolysis of paraoxon (POX), phenylacetate (PA) and beta-naphthylacetate (BNA) was studied in human serum. Based upon correlations between enzyme activities, upon reversible inhibition by EDTA and upon progressive inhibition by iso-OMPA, tabun, eserine and bis-4 nitrophenylphosphate, the following conclusions were drawn about the number and specificity of enzymes involved in the hydrolysis. Two paraxonases hydrolyse paraoxon: one sensitive and the other insensitive to EDTA. The EDTA-sensitive paraoxonase also hydrolysed BNA. The EDTA-insensitive hydrolysis of BNA and PA was attributed to a serine esterase. The EDTA-sensitive hydrolysis of PA is probably due to more than one enzyme, which might be an arylesterase and a carboxylesterase.
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Esterases/sangue , Compostos Organofosforados/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Arildialquilfosfatase , Inibidores da Colinesterase/farmacologia , Colinesterases/metabolismo , Ácido Edético/farmacologia , Esterases/antagonistas & inibidores , Esterases/classificação , Feminino , Humanos , Hidrólise , Cinética , Masculino , Pessoa de Meia-Idade , Ácidos Naftalenoacéticos/metabolismo , Nitrofenóis/farmacologia , Organofosfatos/farmacologia , Compostos Organofosforados/sangue , Paraoxon/metabolismo , Fenilacetatos/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Fisostigmina/farmacologia , Sensibilidade e Especificidade , Especificidade por Substrato , Tetraisopropilpirofosfamida/farmacologia , Tiocolina/análogos & derivados , Tiocolina/metabolismoRESUMO
An enzyme test has been worked out for detecting organophosphorus compounds in water. The test is based on the inhibition of cholinesterase. The detection limits for the "nerve gases" are (microgram/L): Soman 0.12, VX 5.9, Sarin 9.9 and Tabun 26. The detection limit for the organophosphorus pesticide dichlorvos is 50 micrograms/L.
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Compostos Organofosforados/análise , Poluição Química da Água/análise , Ensaios Enzimáticos Clínicos/métodos , Abastecimento de ÁguaRESUMO
Tyrosine 109 in the acetylcholinesterase sequence of Drosophila melanogaster corresponds to an aspartate in vertebrate cholinesterases. Mutation of this amino acid to a glycine in the human butyrylcholinesterase gives rise to the 'atypic' phenotype characterized by a reduced activity for charged compounds. We investigated the importance of tyrosine 109 in the Drosophila sequence by in vitro mutagenesis and its expression in the Xenopus oocyte. We show here that tyrosine 109 contributes to the conformation of the active site and the charge of the residue at position 109 is important for catalytic properties. Sensitivity of the enzyme to organophosphorus and carbamate compounds is modified depending on residues present in position 109, therefore this amino acid is a potential site of resistance for insects to insecticides.
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Acetilcolinesterase/metabolismo , Proteínas/metabolismo , Tirosina/metabolismo , Acetilcolinesterase/genética , Animais , Catálise , Inibidores da Colinesterase/farmacologia , DNA/metabolismo , Drosophila melanogaster , Eletroforese em Gel de Poliacrilamida , Regulação da Expressão Gênica , Concentração de Íons de Hidrogênio , Cinética , Mutação , Conformação Proteica , Proteínas/química , Xenopus laevisRESUMO
The inhibition of the human serum cholinesterase phenotypes, usual (U), atypical (A) and heterozygous (UA), by the dimethylcarbamate of (2-hydroxy-5-phenylbenzyl)-trimethylammonium bromide (Ro 02-0683), was followed with benzoylcholine, acetyl-, butyryl- and propionyl-thiocholine as substrates. The first-order rate constants were calculated from the linear part of the inhibition curves and were independent of the substrate used for measuring the enzyme activity. The second-order rate constants for the U, UA and A phenotypes were 8.3 x 10(6), 6.1 x 10(6) and 0.05 x 10(6) M-1 min-1, respectively. The constant of the enzyme-inhibitor complex for the atypical serum was 7.7 microM, and the rate of carbamylation of the enzyme was 0.386 min-1. The rate of reactivation of carbamylated usual and atypical enzyme was found to be same; the half-time of reactivation was about 3.5 hr. The deviation from the linearity of the inhibition course was explained by spontaneous reactivation of the inhibited enzyme; the theoretical inhibition curves were in good agreement with the experimentally obtained values. The three phenotypes could be distinguished by the rate of inhibition by the dimethylcarbamate, Ro 02-0683, in the progressive phase of inhibition or by the degree of inhibition in the apparent steady-state.
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Inibidores da Colinesterase/farmacologia , Colinesterases/sangue , Isoenzimas/sangue , Compostos de Amônio Quaternário/farmacologia , Colinesterases/genética , Humanos , Isoenzimas/genética , Cinética , FenótipoAssuntos
Envelhecimento/metabolismo , Chumbo/análise , Metais/análise , Dente Decíduo/química , Criança , Pré-Escolar , Cobre/análise , Monitoramento Ambiental , Feminino , Humanos , Indústrias , Ferro/análise , Masculino , Iugoslávia , Zinco/análiseRESUMO
Cyclic peptide disulfides of the general formula H-Cys-(Gly)n-Cys-OH (n = 0-4) were synthesized from the corresponding peptide derivatives [Boc-Cys(Trt)(Gly)-n-Cys(Trt)-OBut] by oxidation with iodine in methanol and by subsequent removal of the terminal groups with trifluoroacetic acid. Acid ionization constants of the obtained peptides were determined by potentiometric titration in aqueous KCl (0.1 mol/L) medium. All compounds have two dissociable hydrogens, corresponding to carboxyl (pK1 = 2.35-2.84) and to terminal amino group (pK2 = 5.61-6.93); pK1 values show first an upward and then a downward trend with the increase in ring size; the opposite is true for pK2 values. These trends could be tentatively attributed to the intramolecular salt bridge (-COO- ----NH+3-) formation.
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Cistina/análise , Peptídeos Cíclicos/síntese química , Sequência de Aminoácidos , Fenômenos Químicos , Físico-Química , Dissulfetos , Ésteres do Ácido Fórmico/análise , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Dados de Sequência Molecular , Peptídeos Cíclicos/análiseRESUMO
The commercially available kits (Test-Combination, Cholinesterase, Boehringer, Mannheim and Test-reagent, Cholinesterase EC 3.1.1.8, Pliva, Zagreb) and reagents prepared in own laboratory for measuring cholinesterase activity (Ellman method) were tested with respect to their stability and the reproducibility of the activity measurements. The reagents of the three sources were shown to be interchangeable and equally stable over a few weeks. The coefficient of variation for within-run measurements by the Ellman method was 2-3% and that for between-run measurements 6%. The stability of the few enzyme standards (Precinorm E, Precinorm U, NBS-serum and native human serum) for the quality control of the measurements was also tested: the most stable was native human serum.