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1.
Fam Cancer ; 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38795222

RESUMO

Telomerase Reverse Transcriptase (TERT) encodes the telomerase reverse transcriptase enzyme and is the most frequently mutated gene in patients with telomeropathies. Heterozygous variants impair telomerase activity by haploinsufficiency and pathogenic variants are associated with bone marrow failure syndrome and predisposition to acute myeloid leukaemia. Owing to their rarity, telomeropathies are often unrecognised and misdiagnosed. Herein, we report a novel TERT gene variant, c.2605G > A p.(Asp869Asn) in a family with hereditary aplastic anaemia. This report emphasises the importance of routine deep genetic screening for rare TERT variants in patients with a family history of cytopenia or aplastic anaemia, which could identify clinically inapparent telomere disorders.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38387341

RESUMO

In 2017, higenamine was added to the World Antidoping Agency's (WADA) Prohibited list under group S3: beta-2 agonists and it is banned for athletes both in - and out of competition. Aim of this study was to characterize the urinary excretion profile of higenamine and its metabolite coclaurine after oral administration of multiple doses of higenamine capsules. For this purpose, an administration study including female basketball players was performed. For the detection of higenamine and cocalurine in the collected urine samples, a new, fast, and highly sensitive quantitative on-line SPE LC HRMS method was developed and validated. The method was applied for the quantification of higenamine and cocalurine in urine and their excretion pattern was defined. Results obtained show substantial inter-individual differences in the excretion profile of higenamine and coclaurine. For higenamine, half-lives were estimated to be between 4 and 27 h, and for coclaurine between 5 and 25 h. Furthermore, the data indicate that the elimination of coclaurine is rate-limited by its formation. Higenamine could be detected at a urine concentration above 10 ng/mL for at least 20 h after the last application for all study participants.


Assuntos
Alcaloides , Dopagem Esportivo , Tetra-Hidroisoquinolinas , Humanos , Feminino , Tetra-Hidroisoquinolinas/urina , Alcaloides/urina , Administração Oral , Detecção do Abuso de Substâncias/métodos
3.
J Fr Ophtalmol ; 39(10): 829-835, 2016 Dec.
Artigo em Francês | MEDLINE | ID: mdl-27843084

RESUMO

PURPOSE: Whether cycloplegics affect standard keratorefractometric and tomographic measurements is unknown. The purpose of our study was to compare the effects of cycloplegics (cyclopentolate and atropine) on corneal shape and refractive power of the eye. METHODS: This study was performed on 84 eyes of 49 study participants. Patients were randomized into two groups: atropine 1% (32 eyes) and cyclopentolate 1% (52 eyes). Corneal tomography was performed with the Orbscan IIz. To evaluate the corneal shape, simulated keratometry values, anterior and posterior best-fit sphere, white-to-white and tangential and axial corneal power were performed for the anterior and posterior corneal surfaces before and during cycloplegia. Pupil diameter, anterior chamber depth, corneal thickness at the 3, 5 and 7mm optical zones, thinnest area of the cornea and corneal thickness at the visual axis were examined. Data were analyzed using an SPSS statistical package. RESULTS: The anterior and posterior BFS (in the atropine 1% group, anterior BFS was P=0.188; anterior BFS in the cyclopentolate group was P=0.227) and tangential and axial corneal power showed no change during cycloplegia in either group. SimK showed no statistical significance. The ACD was deeper when using atropine than cyclopentolate. Corneal thickness remained unchanged during cycloplegia in both groups. Pupil diameter was larger in light-colored irides in the cyclopentolate group than the atropine group. There was no change in W to W before (P=0.473) and during cycloplegia (P=0.287) in either group. CONCLUSIONS: Our results suggest that usage of atropine or cyclopentolate does not alter corneal shape.


Assuntos
Atropina/farmacologia , Córnea/efeitos dos fármacos , Topografia da Córnea , Ciclopentolato/farmacologia , Midriáticos/farmacologia , Soluções Oftálmicas/farmacologia , Adulto , Atropina/administração & dosagem , Córnea/patologia , Córnea/cirurgia , Ciclopentolato/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Midriáticos/administração & dosagem , Refração Ocular/efeitos dos fármacos , Procedimentos Cirúrgicos Refrativos
4.
Diabetes Obes Metab ; 18(7): 711-5, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26663152

RESUMO

The present single-centre, randomized, double-blind, placebo-controlled phase II study investigated the effect of the balanced dual peroxisome proliferator-activated receptor-α/γ agonist aleglitazar on whole-body and liver insulin sensitivity, ß-cell function and other components of cardiometabolic syndrome after 16 weeks of treatment in patients with type 2 diabetes inadequately controlled with metformin monotherapy who received once-daily 150 µg aleglitazar or matching placebo as add-on therapy to metformin. Baseline and 16-week assessments included a two-step hyperinsulinaemic-euglycaemic clamp, followed by a hyperglycaemic clamp, as well as evaluation of glycated haemoglobin (HbA1c), lipids and safety variables. The primary endpoint was change in whole-body insulin sensitivity (M-value) from baseline compared with placebo, derived from the second clamp step. M-value improved significantly from baseline with aleglitazar (n = 16) compared with placebo (n = 24; p = 0.05 for difference between arms). We found statistically significant treatment differences with aleglitazar versus placebo in fasting hepatic insulin resistance index (p = 0.01), and in total glucose disposal (p = 0.03) at the second insulin infusion step. Aleglitazar treatment resulted in significant improvements in HbA1c and lipids and was well tolerated.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Oxazóis/administração & dosagem , Tiofenos/administração & dosagem , Adulto , Idoso , Glicemia/metabolismo , Método Duplo-Cego , Esquema de Medicação , Jejum/sangue , Hemoglobinas Glicadas/metabolismo , Humanos , Resistência à Insulina/fisiologia , Células Secretoras de Insulina/fisiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Síndrome Metabólica/prevenção & controle , Pessoa de Meia-Idade , PPAR alfa/agonistas , PPAR gama/agonistas , Resultado do Tratamento
5.
Diabetes Obes Metab ; 17(6): 560-565, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25728612

RESUMO

AIMS: To evaluate the potential efficacy, safety and tolerability of aleglitazar as monotherapy or add-on therapy to metformin or to a sulphonylurea (either alone or in combination with metformin). METHODS: We conducted a pooled analysis of data from three randomized phase III clinical trials of aleglitazar in patients with type 2 diabetes (n = 591). The three studies focused on: (i) aleglitazar alone; (ii) aleglitazar and metformin; and (iii) aleglitazar and sulphonylurea with or without metformin. Patients were randomized to 26 weeks' treatment with aleglitazar 150 µg/day or placebo. The primary endpoint was change in glycated haemoglobin (HbA1c) concentration from baseline to week 26. Secondary endpoints included changes in lipids, fasting plasma glucose and homeostatic model assessment of insulin resistance (HOMA-IR) at week 26. RESULTS: Reductions in HbA1c concentration from baseline to week 26 were statistically significantly greater with aleglitazar than with placebo. Aleglitazar treatment was associated with more beneficial changes in lipid profiles and HOMA-IR values than was placebo. Aleglitazar was generally well tolerated, with no reports of congestive heart failure. The incidence of peripheral oedema was similar in both groups. Change in body weight was +1.37 kg with aleglitazar and -0.53 kg with placebo. Hypoglycaemia was more frequently reported with aleglitazar (7.8%) than with placebo (1.7%), a result probably driven by the type of background medication. CONCLUSIONS: Development of aleglitazar was halted because of a lack of cardiovascular efficacy and peroxisome proliferator-activated receptor-related side effects in patients with type 2 diabetes post-acute coronary syndrome; however, in the present studies, aleglitazar was well tolerated and effective in improving HbA1c, insulin resistance and lipid variables.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Metformina/uso terapêutico , Oxazóis/uso terapêutico , Compostos de Sulfonilureia/uso terapêutico , Tiofenos/uso terapêutico , Glicemia/análise , Diabetes Mellitus Tipo 2/sangue , Quimioterapia Combinada , Jejum/sangue , Feminino , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemia/induzido quimicamente , Resistência à Insulina/fisiologia , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade
6.
J Appl Microbiol ; 116(5): 1344-58, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24484429

RESUMO

AIMS: To evaluate the food safety and spoilage risks associated with psychrotrophic Bacillus cereus group bacteria for the egg product industry and to search for relevant risk markers. METHODS AND RESULTS: A collection of 68 psychrotrophic B. cereus group isolates, coming from pasteurized liquid whole egg products, was analysed through a principal component analysis (PCA) regarding their spoilage and food safety risk potentials. The principal component analysis showed a clear differentiation between two groups within the collection, one half of the isolates representing a safety risk and the other half a spoilage risk. CONCLUSIONS: Relevant risk markers were highlighted by PCA, that is (i) for the food safety risk, the presence of the specific 16S rDNA-1m genetic signature and the ability to grow at 43°C on solid medium and (ii) for the spoilage risk, the presence of the cspA genetic signature. SIGNIFICANCE AND IMPACT OF THE STUDY: This work represents a first step in the development of new diagnostic technologies for the assessment of the microbiological quality of foods likely to be contaminated with psychrotrophic B. cereus group bacteria.


Assuntos
Bacillus cereus/classificação , Ovos/microbiologia , Microbiologia de Alimentos , Bacillus cereus/genética , Bacillus cereus/crescimento & desenvolvimento , Bacillus cereus/isolamento & purificação , Proteínas de Bactérias/genética , Marcadores Genéticos , Genótipo , Proteínas de Choque Térmico/genética , Humanos , Fenótipo , RNA Ribossômico 16S/genética , Proteínas de Ligação a RNA/genética , Medição de Risco
7.
Diabet Med ; 30(1): 109-13, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22937895

RESUMO

AIMS: To compare the efficacy and safety of once-weekly taspoglutide with insulin glargine in patients with advanced Type 2 diabetes failing metformin and sulphonylurea combination therapy. METHODS: This open-label, parallel-group, multi-centre trial randomized 1049 patients continuing metformin 1:1:1 to taspoglutide 10 mg once weekly, taspoglutide 20 mg once weekly or insulin glargine once daily with forced titration to fasting plasma glucose ≤ 6.1 mmol/l. Sulphonylureas were discontinued before randomization. The primary endpoint was change in HbA(1c) after 24 weeks. RESULTS: After 24 weeks, least-square mean changes from baseline in HbA(1c) in patients receiving taspoglutide 10 mg [-8 mmol/mol (se 1)] [-0.77% (se 0.05)] or taspoglutide 20 mg [-11 mmol/mol (se 1)] [-0.98% (se 0.05)] were non-inferior to insulin glargine [-9 mmol/mol (se 1)] [-0.84% (se 0.05)]; treatment difference of 0.07% (95% CI -0.06 to 0.21) and -0.14% (95% CI -0.28 to -0.01), for taspoglutide 10 and 20 mg, respectively, vs. insulin glargine. Taspoglutide was associated with more adverse events (mainly gastrointestinal) and significantly less hypoglycaemia than insulin glargine. CONCLUSIONS: Compared with insulin glargine, taspoglutide provided non-inferior HbA(1c) reductions associated with less hypoglycaemia, but more gastrointestinal adverse events.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Hipoglicemiantes/administração & dosagem , Insulina de Ação Prolongada/administração & dosagem , Peptídeos/administração & dosagem , Adolescente , Adulto , Idoso , Diabetes Mellitus Tipo 2/sangue , Esquema de Medicação , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemiantes/efeitos adversos , Insulina Glargina , Insulina de Ação Prolongada/efeitos adversos , Masculino , Metformina/administração & dosagem , Metformina/efeitos adversos , Pessoa de Meia-Idade , Peptídeos/efeitos adversos , Resultado do Tratamento , Adulto Jovem
8.
Environ Int ; 49: 115-9, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-23010255

RESUMO

A main known culprit causing amnesic shellfish poisoning in humans is domoic acid (DA). The toxin appearance in sea waters (by counting the toxin producing algae) and consequently in shellfish is closely monitored to prevent acute intoxications with gastrointestinal symptoms and neurological signs. However it is assumed that there might be some chronic problems with repetitive exposures to the toxin in animals. In humans this is greatly unknown and it is mostly assessed by relating reported toxin episodes and representative consumption data. Although in Belgium no alarming outbreaks have been reported in recent years, different concentrations of DA have been found in shellfish samples. In this study the human acute and chronic exposure to DA through shellfish consumption was evaluated by linking the data of DA concentrations in samples collected in the scope of the National Food control program in the period 2004-2009 and consumption data obtained from the National Belgian Food Consumption Survey including 3245 adults. The found level of toxin was highest in scallops while lowest in mussels. The mean usual long-term intake of molluscs such as scallops, mussels and oysters for the whole Belgian population was from 0.10 g/day for scallops to 1.21 g/day for mussels. With average portion size estimated to be 56-108 g/day depending on the shellfish source it was calculated that less than 1% of the population would be at risk of acute intoxication. Using a medium bound approach, 5-6% of the population shows chronic exposure exceeding the tolerable daily intake of 0.075 µg/kg bw per day with scallops being the most probable toxin vector when using lower (68.5%) and medium (45.6%) bound concentrations.


Assuntos
Ácido Caínico/análogos & derivados , Frutos do Mar/estatística & dados numéricos , Poluentes Químicos da Água/análise , Animais , Bélgica , Monitoramento Ambiental , Humanos , Ácido Caínico/análise , Água do Mar/química , Intoxicação por Frutos do Mar/epidemiologia
9.
J Sports Med Phys Fitness ; 52(4): 382-92, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22828460

RESUMO

AIM: The purpose of the current study was to examine the effect of Astaxanthin (Asx) supplementation on muscle enzymes as indirect markers of muscle damage, oxidative stress markers and antioxidant response in elite young soccer players. METHODS: Thirty-two male elite soccer players were randomly assigned in a double-blind fashion to Asx and placebo (P) group. After the 90 days of supplementation, the athletes performed a 2 hour acute exercise bout. Blood samples were obtained before and after 90 days of supplementation and after the exercise at the end of observational period for analysis of thiobarbituric acid-reacting substances (TBARS), advanced oxidation protein products (AOPP), superoxide anion (O2•¯), total antioxidative status (TAS), sulphydril groups (SH), superoxide-dismutase (SOD), serum creatine kinase (CK) and aspartate aminotransferase (AST). RESULTS: TBARS and AOPP levels did not change throughout the study. Regular training significantly increased O2•¯ levels (main training effect, P<0.01). O2•¯ concentrations increased after the soccer exercise (main exercise effect, P<0.01), but these changes reached statistical significance only in the P group (exercise x supplementation effect, P<0.05). TAS levels decreased significantly post- exercise only in P group (P<0.01). Both Asx and P groups experienced increase in total SH groups content (by 21% and 9%, respectively) and supplementation effect was marginally significant (P=0.08). Basal SOD activity significantly decreased both in P and in Asx group by the end of the study (main training effect, P<0.01). All participants showed a significant decrease in basal CK and AST activities after 90 days (main training effect, P<0.01 and P<0.001, respectively). CK and AST activities in serum significantly increased as result of soccer exercise (main exercise effect, P<0.001 and P<0.01, respectively). Postexercise CK and AST levels were significantly lower in Asx group compared to P group (P<0.05) CONCLUSION: The results of the present study suggest that soccer training and soccer exercise are associated with excessive production of free radicals and oxidative stress, which might diminish antioxidant system efficiency. Supplementation with Asx could prevent exercise induced free radical production and depletion of non-enzymatic antioxidant defense in young soccer players.


Assuntos
Antioxidantes/farmacologia , Suplementos Nutricionais , Músculo Esquelético/enzimologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/sangue , Futebol/fisiologia , Adolescente , Biomarcadores/sangue , Método Duplo-Cego , Teste de Esforço , Humanos , Masculino , Músculo Esquelético/patologia , Xantofilas/farmacologia
10.
J Oral Rehabil ; 39(10): 785-90, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22672313

RESUMO

Obstructive sleep apnoea (OSA) is one of the most common sleep disorders in elderly and represents a special problem for elderly patients. Elderly patients use a large number of drugs that might have an influence on the upper airway structure, anxiolytics or benzodiazepines being the most common. The aim of this study was to examine the effectiveness of mild or moderate OSA treatment with mandibular advance oral appliance in older lorazepam users compared with the age-matched lorazepam-free patients. A total of 40 functionally independent patients with the age of 65-74 were enrolled in the study. All included patients were found to suffer from at least two of the existing OSA symptoms (snoring, sleep fragmentation, daytime sleepiness) and were diagnosed with mild or moderate OSA after nocturnal polysomnography. Patients were divided into two groups. The experimental group consisted of 20 patients who used lorazepam in their daily therapy, and a control group consisted of 20 patients who did not take lorazepam. A mandibular advance appliance was made individually for each patient. Patients involved in the study were not overweight and were suggested to practise sleeping on the side and reduce alcohol consumption during the study. The study has shown that mandibular advance oral appliances were responsible for complete control of the OSA in over 37% of cases (15 patients). Patients have also reported substantial improvement in the symptoms; 80% of them reported that they had snored less, slept better (94%) and have not experienced daytime sleepiness (100%).


Assuntos
Ansiolíticos/uso terapêutico , Lorazepam/uso terapêutico , Aparelhos Ortodônticos , Apneia Obstrutiva do Sono/terapia , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Projetos Piloto , Polissonografia , Apneia Obstrutiva do Sono/tratamento farmacológico , Resultado do Tratamento
11.
Pharmacopsychiatry ; 44(5): 165-8, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21751125

RESUMO

INTRODUCTION: Although several adverse effects of antidepressants on the gastrointestinal tract have been described (bleeding, constipation, dolichocolon), their influence on gallbladder motility was not investigated.The aim of our study was to investigate the effects of selected antidepressants on gallbladder emptying in patients with major depression. METHODS: The study was set up as an open clinical trial, with the same intervention (ingestion of test meal provoking gallbladder emptying) undertaken in 112 patients with major depression. There were 30 patients not taking antidepressants (the control group), 25 patients taking amitriptyline, 30 patients taking maprotiline, and 27 patients taking fluoxetine. The volume of gallbladder in the study patients was measured by ultrasonography before the test meal, and 15, 30, 45 and 60 min after the meal. RESULTS: 1 h after ingestion of the study meal, the amitriptyline group showed incomplete gallbladder emptying (F=10.829, df=3, p=0.000; mean residual volume 11.0±6.1 mL), while in the control, maprotiline and fluoxetine groups emptying of gallbladder was complete (mean residual volumes 5.0±3.3 mL, 5.6±3.7 mL and 5.7±2.3 mL, respectively). DISCUSSION: In patients with cholecystitis, it would be wise to use antidepressants which do not impair gallbladder emptying, like maprotiline or fluoxetine, and to avoid amitriptyline.


Assuntos
Amitriptilina/efeitos adversos , Transtorno Depressivo Maior/tratamento farmacológico , Fluoxetina/efeitos adversos , Esvaziamento da Vesícula Biliar/efeitos dos fármacos , Vesícula Biliar/patologia , Maprotilina/efeitos adversos , Adolescente , Adulto , Idoso , Antidepressivos/efeitos adversos , Estudos de Casos e Controles , Transtorno Depressivo Maior/complicações , Feminino , Vesícula Biliar/diagnóstico por imagem , Vesícula Biliar/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão/efeitos dos fármacos , Ultrassonografia
12.
Artigo em Inglês | MEDLINE | ID: mdl-20503127

RESUMO

An exposure assessment was performed to estimate the usual daily intake of sulfites in the Belgian adult population. Food consumption data were retrieved from the national food consumption survey. In a first step, individual food consumption data were multiplied with the maximum permitted use levels for sulfites, expressed as sulphur dioxide, per food group (Tier 2). In a second step, on the basis of a literature review of the occurrence of sulfites in different foods, the results of the Tier 2 exposure assessment and available occurrence data from the control programme of the competent authority, a refined list of foods was drafted for the quantification of sulphite. Quantification of sulphite was performed by a high-performance ion chromatography method with eluent conductivity detector in beers and potato products. Individual food consumption data were then multiplied with the actual average concentrations of sulfite per food group, or the maximum permitted levels in case actual levels were not available (partial Tier 3). Usual intakes were calculated using the Nusser method. The mean intake of sulfites was 0.34 mg kg(-1) bw day(-1) (Tier 2), corresponding to 49% of the acceptable daily intake (ADI) and 0.19 mg kg(-1) bw day(-1), corresponding to 27% of the ADI (partial Tier 3). The food group contributing most to the intake of sulfites was wines. The results showed that the intake of sulfites is likely to be below the ADI in Belgium. However, there are indications that high consumers of wine have an intake around the ADI.


Assuntos
Bebidas Alcoólicas/análise , Dieta , Análise de Alimentos , Conservantes de Alimentos/administração & dosagem , Conservantes de Alimentos/análise , Sulfitos/administração & dosagem , Sulfitos/análise , Adolescente , Adulto , Idoso , Algoritmos , Bélgica , Calibragem , Cromatografia Líquida de Alta Pressão , Bases de Dados Factuais , Feminino , Conservantes de Alimentos/normas , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Vinho/análise , Adulto Jovem
13.
Artigo em Inglês | MEDLINE | ID: mdl-19680971

RESUMO

An exposure assessment was performed to estimate average daily benzoic acid intake for Belgian adults. Food consumption data were retrieved from the national food-consumption survey. As a first step, individual food-consumption data were multiplied with the maximum permitted use levels for benzoic acid per food group (Tier 2). As a second step, a label survey to identify the foods where benzoic acid is effectively used as an additive and a literature review of the possible occurrence of benzoic acid as a natural substance were performed. With this information, a refined list of foods was drafted for the quantification of benzoic acid, which was performed by a high-performance liquid chromatography (HPLC) method, optimized and validated for this purpose. Individual food-consumption data were then multiplied with the actual average concentrations of benzoic acid per food group (Tier 3). Usual intakes were calculated using the Nusser method. The mean benzoic acid intake was 1.58 mg kg(-1) body weight day(-1) (Tier 2) and 1.25 mg kg(-1) body weight day(-1) (Tier 3). In Tier 2, men exceeded the acceptable daily intake (ADI) of 5 mg kg(-1) body weight day(-1) at the 99th percentile. The greatest contributors to the benzoic acid intake were soft drinks. Benzoic acid as a natural substance represents only a small percentage of the total intake. The results show that actual benzoic acid intake is very likely to be below the ADI. However, there is a need to collect national food-consumption data for children as they might be more vulnerable to an excessive intake.


Assuntos
Ácido Benzoico/análise , Aditivos Alimentares/análise , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bélgica , Ácido Benzoico/administração & dosagem , Cromatografia Líquida de Alta Pressão/métodos , Dieta , Registros de Dieta , Inquéritos sobre Dietas , Feminino , Aditivos Alimentares/administração & dosagem , Humanos , Legislação sobre Alimentos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
14.
Genetika ; 44(3): 329-35, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18664136

RESUMO

The Amy-locus polymorphism of Drosophila subobscura is used as a model-system for an experimental population genetic study of adaptive significance of alpha-amylase activity on substrates of different carbohydrate compositions. So far, fitness components have not commonly been included in ecological-genetic studies of alpha-amylase polymorphism in this species. In the present paper fitness components are analyzed in relation to different amylase activities in D. subobscura individuals homozygous for "slow" and "fast" Amy allele, associated with substrates of different carbohydrate compositions. The results indicate a significant effect of substrate carbohydrate composition on fitness components of the genotypes homozygous for S or F Amy allele in D. subobscura through their enzyme activity.


Assuntos
Amilases/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/enzimologia , Evolução Molecular , Polimorfismo Genético , Adaptação Fisiológica/genética , Amilases/genética , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Maltose/metabolismo , Amido/metabolismo , Especificidade por Substrato
15.
Acta Biol Hung ; 59(1): 47-56, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18401944

RESUMO

We analyzed the developmental time, egg-to-adult viability, and developmental stability (fluctuating wing size asymmetry) in Drosophila subobscura, maintained for six generations on different concentrations of lead. Development time is significantly affected by generation and lead concentration, but interaction of these factors is not a significant source of variability for this fitness component. Generation and the interaction generation x concentration of lead significantly affect egg-to-adult viability. Levene's test of heterogeneity of variance showed that variability of FA is not significant in any of the samples. Within both lead concentrations females showed significantly higher FA indices for the wing width than males. Within sexes, a significantly higher FA was found only in females for wing width FA between the control and the lower concentration of lead. The results show that if strong relationship between FA and the studied fitness components exists, it results in a stronger selection of unstable genotypes under lead as a stress factor and, consequently, FA needs to be used with caution as a biomarker in natural populations under environmental stress.


Assuntos
Drosophila/crescimento & desenvolvimento , Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Animais , Biomarcadores , Relação Dose-Resposta a Droga , Drosophila/anatomia & histologia , Drosophila/efeitos dos fármacos , Poluentes Ambientais/farmacologia , Feminino , Chumbo/farmacologia , Masculino , Asas de Animais/anatomia & histologia , Asas de Animais/efeitos dos fármacos , Asas de Animais/crescimento & desenvolvimento
16.
Lett Appl Microbiol ; 46(5): 536-41, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18363653

RESUMO

AIMS: The study describes the effects of heating temperature and exposure time on the thermal stability of cereulide under different conditions (pH, presence/absence of oil phase and cereulide concentration). METHODS AND RESULTS: Cereulide heat inactivation was investigated at 100, 121 and 150 degrees C under different alkaline pH values (8.6-10.6) and in the presence of oil phase (0.6-1.4%). Three different cereulide concentrations (0.5, 5 and 6 microg ml(-1)) were used. Cereulide detection was performed with computer-aided semen analyzer and with HPLC-MS. Highly alkaline pH was needed to achieve inactivation. At lower cereulide concentrations less drastic conditions were needed. Removal of alkaline buffer after the heat treatment resulted in the recovery of toxic activity. CONCLUSIONS: Heat stability of cereulide has been proved to be remarkable, even at highly alkaline pH values, at all temperatures tested. The loss of activity appeared to be reversible. SIGNIFICANCE AND IMPACT OF THE STUDY: The study demonstrates the inability of any heat treatment used in the food industry to inactivate cereulide. Food safety has to rely on prevention and cold chain maintenance. Cleaning practices also need to be adapted as cereulide may remain in its active form upon sterilization of used material.


Assuntos
Bacillus cereus/química , Toxinas Bacterianas/química , Toxinas Bacterianas/metabolismo , Depsipeptídeos/química , Depsipeptídeos/metabolismo , Manipulação de Alimentos , Bacillus cereus/metabolismo , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Espectrometria de Massas
18.
Hereditas ; 143(2006): 41-6, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17362332

RESUMO

Drosophila subobscura is a wild Drosophila species that is spread over almost all of Europe. It possesses an uniquely rich inversion polymorphism on all five long chromosomes. This polymorphism is to a certain degree associated with the variation and dynamics of ecological factors in space and time. We analyzed the changes of inversion polymorphism components of Drosophila subobscura flies maintained on media with different concentrations of lead in laboratory conditions. The effects of lead on inversion polymorphism were observed by cytological analysis of gene arrangements on all of the five acrocentric chromosomes, as well as by cytological analysis of karyotypes on all of the four autosomes. The frequencies of particular gene arrangements on the four autosomes changed significantly in the samples maintained on medium not supplemented with lead. The frequencies of some gene arrangements on all of the five acrocentric chromosomes changed significantly in the flies maintained on media supplemented with lead. The length of exposure to different lead concentrations results in a significant change in the frequency of a few gene arrangements on two autosomes. However, the results show that different concentrations of lead, as well as the length of exposure, do not affect major parameters of inversion polymorphism. The results suggest that some gene arrangements could be linked with adaptive processes in evolving heavy metal resistance.


Assuntos
Inversão Cromossômica , Drosophila/genética , Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Polimorfismo Genético , Animais , Relação Dose-Resposta a Droga , Drosophila/classificação , Drosophila/efeitos dos fármacos , Europa (Continente) , Frequência do Gene , Ordem dos Genes/efeitos dos fármacos , Variação Genética , Cariotipagem
20.
Genes Genet Syst ; 78(1): 23-8, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12655135

RESUMO

Biochemical properties of enzyme alpha-amylase were surveyed in Drosophila obscura Old world group of species (D. subobscura, D. ambigua, D. obscura and D. tristis) sampled in the same habitat, with the aim to reveal some ecological and evolutionary aspects of amylase polymorphism, which has been studied extensively in D. subobscura, but not compared with other species in the group. The data obtained show that D. subobscura is distinct from the other three species regarding all biochemical amylase properties. Such a divergence also correlates with the niche breadth and relative abundance of these species in the same habitat.


Assuntos
Adaptação Fisiológica/genética , Drosophila/genética , alfa-Amilases/genética , Animais , Evolução Biológica , Drosophila/enzimologia , Cinética , alfa-Amilases/metabolismo
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