RESUMO
AIM: The aim of this study was to describe the technique of DCMRL to identify central lymphatic abnormalities in patients with primary lymphatic anomalies and discuss utility of the findings. MATERIALS AND METHODS: Twenty-eight patients with primary lymphatic abnormalities underwent dynamic magnetic resonance imaging (MRI) following injection of gadolinium directly into inguinal lymph nodes at a tertiary lymphovascular referral center. RESULTS: Technical success was achieved in 23 patients (82.1%). Pathological imaging findings included obstructed, hypoplastic, or absent lymphatic channels with collateralization/rerouting or reflux of flow, lymphangiectasia, lymphatic pseudoaneurysms, and lymph leaks. Protocol modifications for improved imaging are highlighted including technical aspects of lymph node injection, image acquisition and MRI parameters. In two patients, imaging findings warranted embolization of the abnormal lymphatic channels with subsequent symptomatic improvement. CONCLUSION: DCMRL has been shown to be a safe, reproducible technique in patients with primary lymphatic anomalies enabling imaging of the central lymphatic system.
Assuntos
Meios de Contraste , Anormalidades Linfáticas , Linfografia , Imageamento por Ressonância Magnética , Humanos , Feminino , Masculino , Imageamento por Ressonância Magnética/métodos , Adulto , Anormalidades Linfáticas/diagnóstico por imagem , Criança , Adolescente , Pessoa de Meia-Idade , Linfografia/métodos , Pré-Escolar , Adulto Jovem , Linfonodos/diagnóstico por imagem , Lactente , IdosoRESUMO
INTRODUCTION: Fecal and urinary incontinence are common disorders in children. Obesity and its associated comorbidities have become increasingly common, and a relation between obesity, nocturia, incontinence, and nocturnal enuresis has been suggested. OBJECTIVE: This large scale population study aims to determine the prevalence of fecal incontinence (FI), daytime urinary incontinence (DUI), nocturnal enuresis (NE), and nocturia in children at school entry and in adolescence and to clarify whether obesity is associated to any of the aforementioned symptoms. STUDY DESIGN: First-grade children and their parents and adolescents in the seventh to ninth grades were interviewed in relation to school nurse visits. The interview included questions on whether incontinence or nocturia were experienced at least once per month. The participants' age was recorded, and weight and height were measured. Body mass index (BMI) was calculated and age standardized by the use of BMI-standard deviation score (SDS), with reference to World Health Organization normative BMI data. Obesity was defined as BMI-SDS >2. Associations between obesity and incontinence and nocturia were quantified by odds ratio (OR). RESULTS: Completed interview questionnaires and measurements were obtained from 4002 children (95.1%) in the child population and 2801 adolescents (84.4%) in the adolescent population. The mean age of children was 6.45 ± 0.39 years, and 4.4% were obese. Overall 11.2% reported FI, 21.8% DUI, 16.8% NE, and 31.4% experienced nocturia. Obesity was associated with FI in first-grade boys (OR 1.86 compared with normal weight). Mean age of adolescents was 13.9 ± 0.85 years, and 7.6% of adolescent boys and 5.5% of the girls were obese. Fecal incontinence was reported by 2.1% of the adolescents, 4.5% had DUI, 1.0% stated to have NE, and 32.3% reported nocturia. Obesity was significantly associated with nocturia in adolescents (OR 1.74-2.01). DISCUSSION: The prevalence of nocturia seems constant throughout childhood and adolescent life; this has not previously been documented. Incontinence is very common at school entry, with DUI reported more frequently than enuresis by both children and adolescents. Obesity is associated with nocturia in adolescents and FI in first-grade boys, but no significant association between obesity and NE or DUI is found. Strength of this study is the very high participation rates, but the study does not reveal information on previous treatment, subtype, or severity of symptoms. CONCLUSIONS: Incontinence is very common in children. One-third of both children and adolescents experience nocturia. Obesity is associated with FI in first-grade boys and nocturia in adolescents.
Assuntos
Índice de Massa Corporal , Incontinência Fecal/epidemiologia , Noctúria/epidemiologia , Obesidade Infantil/complicações , Incontinência Urinária/epidemiologia , Adolescente , Criança , Dinamarca/epidemiologia , Incontinência Fecal/etiologia , Feminino , Seguimentos , Humanos , Masculino , Noctúria/etiologia , Prevalência , Estudos Retrospectivos , Inquéritos e Questionários , Incontinência Urinária/etiologiaRESUMO
Oculodentodigital syndrome (ODD; OMIM 164200) is a congenital condition with phenotypic features most commonly affecting the face, eyes, dentition and digits. The condition is caused by mutations in the GJA1 gene on chromosome 6. GJA1 codes for connexin 43, a gap junction protein important in providing cell to cell communication and is expressed in lymphatic valves. We present a patient with a clinical and molecular diagnosis of ODD and lower limb lymphoedema. Sanger sequencing of family members confirmed that the missense, p.K206R, GJA1 mutation segregated with the phenotype suggestive of causality. To our knowledge this association has not been reported previously. This is therefore the second connexin gene associated with a lymphoedema phenotype after the recent publication of GJC2 (connexin 47) as a cause of four limb lymphoedema.
Assuntos
Conexina 43/genética , Anormalidades Craniofaciais/genética , Anormalidades do Olho/genética , Deformidades Congênitas do Pé/genética , Linfedema/genética , Mutação , Sindactilia/genética , Anormalidades Dentárias/genética , Anormalidades Múltiplas/genética , Adulto , Anormalidades Craniofaciais/diagnóstico , Éxons , Anormalidades do Olho/diagnóstico , Feminino , Deformidades Congênitas do Pé/diagnóstico , Humanos , Linfedema/diagnóstico , Linfocintigrafia , Linhagem , Fenótipo , Sindactilia/diagnóstico , Anormalidades Dentárias/diagnósticoRESUMO
Historically, primary lymphoedema was classified into just three categories depending on the age of onset of swelling; congenital, praecox and tarda. Developments in clinical phenotyping and identification of the genetic cause of some of these conditions have demonstrated that primary lymphoedema is highly heterogenous. In 2010, we introduced a new classification and diagnostic pathway as a clinical and research tool. This algorithm has been used to delineate specific primary lymphoedema phenotypes, facilitating the discovery of new causative genes. This article reviews the latest molecular findings and provides an updated version of the classification and diagnostic pathway based on this new knowledge.
Assuntos
Algoritmos , Linfedema/classificação , Linfedema/diagnóstico , HumanosAssuntos
Proteínas de Ligação ao Cálcio/genética , Hidropisia Fetal/genética , Anormalidades Linfáticas/genética , Mutação , Proteínas Supressoras de Tumor/genética , Criança , Pré-Escolar , Anormalidades Craniofaciais/diagnóstico , Anormalidades Craniofaciais/genética , Diagnóstico Diferencial , Feminino , Feto , Predisposição Genética para Doença , Doenças dos Genitais Masculinos/diagnóstico , Doenças dos Genitais Masculinos/genética , Humanos , Hidropisia Fetal/diagnóstico , Lactente , Recém-Nascido , Linfangiectasia Intestinal/diagnóstico , Linfangiectasia Intestinal/genética , Anormalidades Linfáticas/diagnóstico , Linfedema/diagnóstico , Linfedema/genética , MasculinoRESUMO
Primary lymphoedema is a clinically and genetically heterogeneous group of disorders characterized by disruption of the lymphatic system. To date, the majority of the causative genes in primary lymphoedema have been identified through linkage analysis in large families with multiple affected subjects. Studies aimed at isolating additional genes responsible for primary lymphoedema have been hampered by cohorts comprised primarily of sporadic cases and small affected kindreds. In the absence of genetic heterogeneity, recent development of massively parallel DNA sequencing technology, specifically exome sequencing, has provided novel paradigms for disease gene identification in such cohorts. In this review, we summarize the novel approaches to disease gene discovery with massively parallel sequencing also known as Next Generation Sequencing (NGS), and show how the selection of unrelated affected cases from clinically homogenous phenotypic subclassifications is proving to be a successful approach for disease gene discovery in primary lymphoedema.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Linfedema/genética , Análise de Sequência de DNA , Ligação Genética , Humanos , Linfedema/congênito , Linfedema/diagnósticoRESUMO
BACKGROUND: A 23-year-old male was referred to our clinic with diagnosis of idiopathic isolated growth hormone deficiency. A detailed family history revealed short stature and swelling of legs which only affected females in four generations of his family. METHODS: Combined pituitary function tests revealed growth hormone deficiency, secondary hypothyroidism and hypoprolactinemia in the proband. His mother had hypoprolactinemia and growth hormone deficiency. A diagnosis of inherited combined pituitary deficiency due to a PIT-1 mutation was suspected in view of the short stature with associated multiple pituitary hormone deficiencies. RESULTS: A mutation was identified in PIT-1 (POU1F1), 196C>T, which produces the amino acid change P24L in exon 1. The mutation was also found in the mother of the proband but not in his phenotypically normal half-sister. CONCLUSION: The case shows a novel association of two rare conditions Pit-1 mutation and lipoedema in a family that has not been described before. It also allows formulation of hypothesis on the interaction of growth hormone and sex steroids resulting in abnormal fat distribution in predisposed subjects at the time of puberty.
Assuntos
Hormônio do Crescimento Humano/deficiência , Hiperlipidemias/genética , Fator de Transcrição Pit-1/genética , Feminino , Humanos , Hipotireoidismo/genética , Masculino , Mutação , Linhagem , Polimorfismo de Nucleotídeo Único , Adulto JovemRESUMO
Milroy disease (hereditary lymphoedema type I, MIM 153100) is a congenital onset primary lymphoedema with autosomal dominant inheritance. Mutations in the gene, vascular endothelial growth factor receptor 3, VEGFR3 (FLT4), are known to cause Milroy disease, but there is uncertainty about the prevalence of VEGFR3 mutations in patients with primary lymphoedema and more specifically in those with a phenotype that resembles Milroy disease. This study aims to address this issue and thereby delineate the Milroy disease phenotype. Fifty-two patients with primary lymphoedema were analysed for mutations in the coding regions of VEGFR3. Patients were divided into four groups: Typical Milroy disease with family history (group I), typical Milroy disease with no family history (group II), atypical Milroy disease (group III), and complex primary lymphoedema (group IV). Results demonstrated that with rigorous phenotyping the likelihood of detecting VEGFR3 mutations is optimised. Mutation prevalence is 75% in typical Milroy patients with a family history (group I) and 68% if positive family history is not a diagnostic criterion. A positive family history is not essential in Milroy disease. The likelihood of detecting VEGFR3 mutations in patients who have a phenotype which is not typical of Milroy disease is very small (<5%). For the 22 mutation positive patients, 14 novel VEGFR3 mutations were identified, two of which were in exon 22 and one in exon 17, confirming that these exons should be included in VEGFR3 analysis. No mutations were found outside the kinase domains, showing that analysis of this part of the gene is not useful for Milroy disease patients. VEGFC, which encodes the ligand for VEGFR3, was sequenced in all patients with typical Milroy disease (groups I and II) and no mutations were identified.
Assuntos
Linfedema/genética , Mutação , Fator C de Crescimento do Endotélio Vascular/genética , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/genética , Adolescente , Idade de Início , Criança , Pré-Escolar , Códon , Análise Mutacional de DNA , Feminino , Frequência do Gene , Genes Dominantes , Humanos , Lactente , Recém-Nascido , Linfedema/congênito , Linfedema/diagnóstico , Masculino , Fenótipo , Reação em Cadeia da PolimeraseAssuntos
Doenças em Gêmeos/diagnóstico , Pestanas/anormalidades , Linfedema/diagnóstico , Gêmeos Monozigóticos , Adolescente , Adulto , Criança , Pré-Escolar , Doenças em Gêmeos/genética , Doenças em Gêmeos/patologia , Edema/patologia , Feminino , Fatores de Transcrição Forkhead/genética , Humanos , Lactente , Linfedema/genética , Linfedema/patologia , Masculino , Fenótipo , Síndrome , Varizes/patologiaRESUMO
AIMS: Disturbances in heparan sulphate proteoglycans in patients with diabetic nephropathy might contribute to the pathogenesis of vascular disease in these patients. To investigate this possible link, we measured the heparin-induced, immediate release of eight proteins with heparan sulphate binding properties in patients with nephropathy. METHODS: We studied three groups, Type 1 diabetic patients with (n = 10) or without (n = 15) albuminuria and matched controls (n = 12). Blood samples were obtained before and 5 min after the injection of 40 anti-Xa IU low molecular weight heparin/kg body weight. RESULTS: Lipoprotein lipase increased more in diabetic patients without albuminuria than in controls and patients with albuminuria [261 (170-293) vs. 177 (103-438), P < 0.05 and 203 (159-280) mU/ml, P < 0.05]. Total tissue factor pathway inhibitor increased more in the diabetic patients [284 (198-449) and 275 (243-399)] than in the controls [221 (169-289) ng/ml, P < 0.005]. Vitronectin increased significantly only in the diabetic patients with albuminuria. The remaining proteins did not increase significantly (antithrombin, von Willebrand factor, fibronectin) or increased equally in the three investigated groups (extracellular superoxid dismutase and platelet factor 4). CONCLUSIONS: The different release of lipoprotein lipase and vitronectin in diabetic subjects with and without albuminuria may reflect novel aspects of vascular derangement in patients with albuminuria.
Assuntos
Anticoagulantes/farmacologia , Diabetes Mellitus Tipo 1/metabolismo , Nefropatias Diabéticas/metabolismo , Endotélio Vascular/metabolismo , Heparina de Baixo Peso Molecular/farmacologia , Heparina/análogos & derivados , Adulto , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Heparina/metabolismo , Humanos , Injeções , Lipase Lipoproteica/metabolismo , Lipoproteínas/metabolismo , Masculino , Pessoa de Meia-Idade , Fator Plaquetário 4/metabolismo , Proteoglicanas/metabolismo , Superóxido Dismutase/metabolismoRESUMO
Schistosomes are digenean flukes, parasitic of birds, mammals and crocodiles. The family Schistosomatidae contains species of considerable medical and veterinary importance, which cause the disease schistosomiasis. Previous studies, both morphological and molecular, which have provided a good deal of information on the phylogenetics of this group, have been limited in the number of species investigated or the type or extent of molecular data used. This paper presents the most comprehensive phylogeny to date, based on the sequences of 3 genes, complete ribosomal small subunit rRNA and large ribosomal subunit rRNA, and mitochondrial cytochrome oxidase 1, sequenced from 30 taxa including at least 1 representative from 10 of the 13 known genera of the Schistosomatidae and 17 of the 20 recognized Schistosoma species. The phylogeny is examined using morphological characters, intermediate and definitive host associations and biogeography. Theories as to the origins and spread of Schistosoma are also explored. The principal findings are that Ornithobilharzia and Austrobilharzia form a sister group to the Schistosoma; mammalian schistosomes appear paraphyletic and 2 Trichobilharzia species, T. ocellata and T. szidati, seem to be synonymous. The position of Orientobilharzia within the Schistosoma is confirmed, as is an Asian origin for the Schistosoma, followed by subsequent dispersal through India and Africa.
Assuntos
Evolução Molecular , Genes de Helmintos/genética , Filogenia , Schistosomatidae/classificação , Schistosomatidae/genética , Animais , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Geografia , Interações Hospedeiro-Parasita , RNA Ribossômico/genética , Alinhamento de Sequência , Especificidade da EspécieRESUMO
A data set from the metalloproteinase deuterolysin was collected at atomic resolution (1.0 A) with synchrotron radiation. The high resolution allowed the structure to be solved with the new direct-methods program ACORN using the coordinates of the Zn atom as a starting point. The phases obtained from ACORN were of sufficient quality to allow automated building to be carried out in ARP/wARP. Minimal manual rebuilding of the model was required and the structure determination was completed using the maximum-likelihood refinement program REFMAC. The whole process, starting from the processed and merged data and ending with a refined model, required less than 6 h of computational time.
Assuntos
Aspergillus oryzae/enzimologia , Metaloendopeptidases/química , Software , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Modelos Moleculares , Peso Molecular , Conformação ProteicaRESUMO
Recombinant activated coagulation factor VII (rFVIIa) (NovoSeven) was developed for treatment of bleeding in hemophilia patients with inhibitors (antibodies) against factors VIII or IX. rFVIIa initiates the coagulation cascade by binding to tissue factor at the site of injury and causes the formation of sufficient amounts of thrombin to trigger coagulation. Patients with a variety of other coagulation deficiencies than hemophilia characterized by an impaired thrombin generation and life-threatening bleeding have been reported as successfully treated with rFVIIa. Data are now entered into clinical registries established to further monitor this experimental treatment with NovoSeven. rFVIIa is produced free of any added human protein. The amino acid sequence of rFVIIa is identical to plasma-derived FVIIa (pdFVIIa). Posttranslational modifications (i.e., gamma-carboxylations, N- and O-glycosylations) are qualitatively identical in pdFVIIa and rFVIIa although some quantitative differences exist. The activities of rFVIIa and pdFVIIa are indistinguishable. Manufacturing of rFVIIa involves expression in baby hamster kidney (BHK) cells followed by purification, including three ion-exchange and one immunoaffinity chromatography steps. The last anion-exchange chromatography step ensures completion of the autoactivation of recombinant factor VII (rFVII) to rFVIIa. This review describes the mechanism of action, characterization, manufacturing, and preclinical and current clinical evidence for the efficacy and safety of rFVIIa.
Assuntos
Fator VII/química , Fator VII/farmacologia , Microbiologia Industrial/métodos , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologia , Animais , Ensaios Clínicos como Assunto , Clonagem Molecular , Fator VII/uso terapêutico , Fator VIIa , Humanos , Estrutura Molecular , Proteínas Recombinantes/uso terapêutico , Transformação GenéticaRESUMO
The pharmacodynamics of i.v. and subcutaneous (s.c.) tinzaparin sodium compared with heparin in healthy volunteers were studied. A randomized, open-label, five-treatment, five-period-crossover study with a Latin square design was performed in 30 healthy men to estimate tinzaparin pharmacodynamics (anti-Xa and anti-IIa activities) after single-dose i.v. and s.c. administration, to evaluate absolute bioavailability, to determine the effect of a preservative (benzyl alcohol), to evaluate the dose-activity relationship, and to compare tinzaparin with unfractionated heparin. Treatments were (1) heparin 5,000 units s.c., (2) tinzaparin 4,500 anti-Xa IU without preservative s.c., (3) tinzaparin 4,500 anti-Xa IU without preservative i.v., (4) tinzaparin 12,250 anti-Xa IU with preservative s.c., and (5) tinzaparin 4,500 anti-Xa IU with preservative s.c. Blood samples for the measurement of anti-Xa and anti-IIa activities were drawn over 24 hours. Anti-Xa and anti-IIa activities were determined by chromogenic methods; data were analyzed by using a noncompartmental approach. The clearance of tinzaparin based on anti-Xa activity ranged from 1.14 to 2.04 L/hr. The volume of distribution was 3.1-5.0 L, suggesting that the molecular entities responsible for anti-Xa and anti-IIa activities are confined to the intravascular space. Mean peak anti-Xa activity occurred three to four hours after s.c. injection, independent of the dose. The mean half-life of anti-Xa activity after s.c. injection ranged from 3.41 to 4.13 hours and was independent of the dose. The mean absolute bioavailability of s.c. tinzaparin was 86.7%. Intersubject pharmacodynamic variability was low for tinzaparin compared with heparin. Benzyl alcohol did not affect tinzaparin pharmacodynamics. A clear dose-activity relationship was seen for the two fixed doses of tinzaparin (12,250 and 4,500 IU). Single doses of tinzaparin were safe and well tolerated after administration by either route. The anti-Xa profile of tinzaparin supports the pharmacodynamic superiority of low-molecular-weight heparins over standard i.v. heparin administration. This pharmacodynamic study in healthy volunteers indicates that s.c. tinzaparin sodium was well absorbed; the presence of a preservative, benzyl alcohol, did not affect the activity of tinzaparin; and tinzaparin activity is dose-related.
Assuntos
Anticoagulantes/farmacologia , Heparina de Baixo Peso Molecular/farmacologia , Heparina/farmacologia , Adulto , Análise de Variância , Anticoagulantes/administração & dosagem , Área Sob a Curva , Álcool Benzílico , Disponibilidade Biológica , Estudos Cross-Over , Relação Dose-Resposta a Droga , Heparina/administração & dosagem , Heparina de Baixo Peso Molecular/administração & dosagem , Humanos , Injeções Intravenosas , Injeções Subcutâneas , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , TinzaparinaRESUMO
Phytases catalyze the hydrolysis of phosphomonoester bonds of phytate (myo-inositol hexakisphosphate), thereby creating lower forms of myo-inositol phosphates and inorganic phosphate. In this study, cDNA expression libraries were constructed from four basidiomycete fungi (Peniophora lycii, Agrocybe pediades, a Ceriporia sp., and Trametes pubescens) and screened for phytase activity in yeast. One full-length phytase-encoding cDNA was isolated from each library, except for the Ceriporia sp. library where two different phytase-encoding cDNAs were found. All five phytases were expressed in Aspergillus oryzae, purified, and characterized. The phytases revealed temperature optima between 40 and 60 degrees C and pH optima at 5.0 to 6.0, except for the P. lycii phytase, which has a pH optimum at 4.0 to 5.0. They exhibited specific activities in the range of 400 to 1,200 U. mg, of protein(-1) and were capable of hydrolyzing phytate down to myo-inositol monophosphate. Surprisingly, (1)H nuclear magnetic resonance analysis of the hydrolysis of phytate by all five basidiomycete phytases showed a preference for initial attack at the 6-phosphate group of phytic acid, a characteristic that was believed so far not to be seen with fungal phytases. Accordingly, the basidiomycete phytases described here should be grouped as 6-phytases (EC 3.1.3.26).
Assuntos
6-Fitase , Basidiomycota/enzimologia , 6-Fitase/química , 6-Fitase/genética , 6-Fitase/isolamento & purificação , 6-Fitase/metabolismo , Sequência de Aminoácidos , Basidiomycota/classificação , Basidiomycota/genética , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Sequência Conservada , Biblioteca Gênica , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
The X-ray structure of F. oxysporum trypsin has been determined at atomic resolution, revealing electron density in the binding site which was interpreted as a peptide bound in the sites S1, S2 and S3. The structure, which was initially determined at 1.07 A resolution and 283 K, has an Arg in the S1 specificity pocket. The study was extended to 0.81 A resolution at 100 K using crystals soaked in Arg, Lys and Gln to study in greater detail the binding at the S1 site. The electron density in the binding site was compared between the different structures and analysed in terms of partially occupied and overlapping components of peptide, solvent water and possibly other chemical moieties. Arg-soaked crystals reveal a density more detailed but similar to the original structure, with the Arg side chain visible in the S1 pocket and residual peptide density in the S2 and S3 sites. The density in the active site is complex and not fully interpreted. Lys at high concentrations displaces Arg in the S1 pocket, while some main-chain density remains in sites S2 and S3. Gln has been shown not to bind. The free peptide in the S1-S3 sites binds in a similar way to the binding loop of BPTI or the inhibitory domain of the Alzheimer's beta-protein precursor, with some differences in the S1 site.
Assuntos
Fusarium/química , Tripsina/química , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Ligação Proteica , Estrutura Secundária de Proteína , Tripsina/metabolismoRESUMO
Contrary to low-fat meals, high-fat meals are known to cause postprandial factor VII (FVII) activation, but the mechanism is unknown. To study the postprandial FVII activation in detail, 18 young men consumed in randomized order high-fat or low-fat test meals. Fasting and non-fasting blood samples were collected. The high-fat test was associated with an increase in plasma triglyceride and kallikrein concentrations and postprandial FVII activation (p<0.001). Plasma kallikrein was strongly associated with triglycerides in fasting and non-fasting samples (r2=0.74-0.87, p<0.0001), suggesting that triglyceride-rich lipoproteins may activate prokallikrein. Neither plasma triglycerides nor kallikrein and activated FVII were statistically associated. This may suggest that additional factors are involved in the postprandial FVII activation. No clear evidence for a role of tissue factor expression by monocytes, factor XII or insulin in postprandial FVII activation was observed. Tissue factor pathway inhibitor and prothrombin fragment 1+2, a marker of thrombin generation, were not affected postprandially after either the high-fat or the low-fat meals. Our findings indicate that triglyceride-rich lipoproteins activate prokallikrein postprandially, which might form an important initial event in FVII activation after consumption of high-fat meals.
Assuntos
Coagulação Sanguínea/fisiologia , Gorduras na Dieta/administração & dosagem , Fator VII/metabolismo , Calicreínas/sangue , Período Pós-Prandial , Adulto , Coagulação Sanguínea/efeitos dos fármacos , Glicemia , Precursores Enzimáticos/sangue , Fator VII/análise , Fator XII/análise , Fator XII/metabolismo , Fator XIIa/análise , Fator XIIa/metabolismo , Jejum , Humanos , Insulina/sangue , Masculino , Monócitos/metabolismo , Fragmentos de Peptídeos/análise , Protrombina/análise , Triglicerídeos/sangueRESUMO
The coagulant activity of blood coagulation factor VII (FVII:C) can be lowered by changes in lifestyle and by therapeutic intervention, e.g. heparin infusion. The question is, however, whether FVII:C determined ex vivo is a valid measure of the FVII activity in vivo. We measured plasma FVII:C, activated FVII (FVIIa), FVII protein (FVII:Ag), tissue factor pathway inhibitor (TFPI), triglycerides, and free fatty acids (FFA) before and 15 min after infusion of a bolus of unfractionated heparin (50 IU/kg body weight) in 12 healthy subjects. Additionally, we conducted in vitro experiments to investigate the effect of unfractionated heparin and TFPI, which is released from the endothelium by heparin, on FVII:C, FVIIa, and FVII:Ag. Heparin infusion decreased triglycerides and increased FFA and TFPI. This was accompanied by significant reductions in FVIIa, FVII:C and FVII:Ag. In vitro, anti-TFPI antibodies increased FVIIa and FVII:C, and heparin reduced FVIIa. The heparinase Hepzyme was unable to abolish the effect of heparin. There were no in vitro effects on FVII:Ag. We conclude that, due to interference by TFPI and heparin in post-heparin plasma, it is impossible to measure the in vivo FVII activity by means of FVII clotting assays. These assays should therefore not be used to measure the coagulation status of patients in heparin therapy, unless extraordinary precautions are taken to eliminate TFPI and heparin effects ex vivo. The observed effect of heparin on FVII:Ag should be investigated further.
Assuntos
Anticoagulantes/farmacologia , Bioensaio/métodos , Fator VII/análise , Heparina/farmacologia , Lipoproteínas/farmacologia , Adulto , Humanos , Masculino , Sensibilidade e EspecificidadeRESUMO
Tissue factor pathway inhibitor (TFPI) is released to circulating blood after intravenous (i.v.) and subcutaneous (s.c.) injections of heparins, and may thus contribute to the antithrombotic effect of heparins. We have recently shown that total TFPI activity, plasma free TFPI antigen, and heparin releasable TFPI were partially depleted during repeated and continuous i.v. infusion of unfractionated heparin (UFH), but not during s.c. treatment with a low molecular weight heparin (LMWH). The difference may be attributed to a different mode of action or the different mode of administration. In the present randomized cross-over study, s.c. administration of therapeutic doses of UFH was compared with s.c. administration of two LMWHs. 12 healthy male volunteers were treated for 3 d with UFH, 250 U/kg twice daily, dalteparin, 200 U/kg once daily, and enoxaparin, 1.5 mg/kg once daily. Six participants were also treated with UFH, 300 U/kg once daily. On day 5 a single dose of either drug was given. Peak levels of total TFPI activity and free TFPI antigen were detected 1 h after injection, whereas maximal prolongation of activated partial thromboplastin time (APTT) and peak levels of anti-factor Xa activity and anti-factor IIa activity were detected after 4 h. On UFH administered twice daily, free TFPI antigen decreased by 44% from baseline level before the first injection on day 1 to pre-injection level on day 5. On UFH administered once daily, basal free TFPI antigen decreased by 50%, 56% and 27% on day 2, 3 and 5 respectively, compared with day 1. Minimal depletion of TFPI was detected during treatment with LMWHs. The study demonstrates the different modes of action of LMWHs and UFH and may help to explain the superior antithrombotic efficacy of LMWHs.