RESUMO
The aim of this electrochemical study was to ascertain which type of electrochemically deposited carbonyl functionalized polymer represents the most suitable electrode substrate for direct covalent immobilization of biological catalysts (enzymes). For this purpose, a triad of amperometric biosensors differing in the type of conductive polymers (poly-vanillin, poly-trans-cinnamaldehyde, and poly-4-hydroxybenzaldehyde) and in the functioning of selected enzymes (tyrosinase and alkaline phosphatase) has been compared for the biosensing of neurotransmitters (dopamine, epinephrine, norepinephrine, and serotonin) and phenyl phosphates (p-aminophenyl phosphate and hydroquinone diphosphate). The individual layers of the polymers were electrochemically deposited onto commercially available screen-printed carbon electrodes (type C110) using repetitive potential cycling in the linear voltammetric mode. Their characterization was subsequently performed by SEM imaging and attenuated total reflectance FTIR spectroscopy. Molecules of enzymes were covalently bonded to the free carbonyl groups in polymers via the Schiff base formation, in some cases even with the use of special cross-linkers. The as-prepared biosensors have been examined using cyclic voltammetry and amperometric detection. In this way, the role of the carbonyl groups embedded in the polymeric structure was defined with respect to the efficiency of binding enzymes, and consequently, via the final (electro)analytical performance.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Animais , Bovinos , Técnicas Eletroquímicas/métodos , Polímeros/química , Técnicas Biossensoriais/métodos , Eletrodos , Espectroscopia de Infravermelho com Transformada de Fourier , Reprodutibilidade dos TestesRESUMO
Congenital hypothyroidism with fetal goiter is a rare condition associated with severe, but possibly preventable, intrauterine and postnatal complications. Ultrasound examination after 20 weeks of pregnancy enables prenatal diagnosis and early treatment. Due to limited transplacental transport of thyroid hormones, direct intrauterine treatment is needed. So far, only a few reports of fetal goitrous hypothyroidism have been published and no consensus on adequate management exists. We present a case of severe fetal goitrous hypothyroidism diagnosed at 23 gestational weeks treated by sequential intra-amniotic administration of L-thyroxin. Treatment resulted in significant goiter reduction and normalization of amniotic hormone levels, and enabled uncomplicated vaginal delivery at term. Current knowledge regarding prenatal diagnosis and intrauterine treatment were unified and applied within this case and a recommendation for clinical practice is provided in this report.
Assuntos
Hipotireoidismo Congênito/diagnóstico por imagem , Hipotireoidismo Congênito/tratamento farmacológico , Bócio/diagnóstico por imagem , Bócio/tratamento farmacológico , Tiroxina/uso terapêutico , Ultrassonografia Pré-Natal , Adulto , Hipotireoidismo Congênito/complicações , Feminino , Idade Gestacional , Bócio/complicações , Humanos , Gravidez , Tiroxina/administração & dosagem , Resultado do TratamentoRESUMO
Approximately 6-15 % of breast cancer patients are diagnosed with primary ulcerated breast cancer (ULBC). ULBC is known to be associated with short recurrence free and poor overall survival. Therefore, the purpose of this study was to characterize ULBC and compare the histopathological findings with those of non-ulcerative breast cancer (NULBC). A total of 152 ULBCs were evaluated and compared to 304 consecutive non-ulcerated, age-matched breast malignancies. Patients mean age was 65 years (SD = 13.0 ULBC, SD = 14.0 NULBC). ULBC was associated with a higher rate of poorly differentiated tumors (p = < 0.001), as well as larger tumor sizes (p = < 0.001). As expected, the rate of axillary lymph node involvement was higher in ULBC patients (p = <0.001). In addition to that, ULBC was associated with a higher rate of triple negative breast cancer (p = 0.002), and higher Ki67 expression (p = < 0.001). ULBC showed more aggressive histopathological features in comparison to NULBC which may contribute to the generally known poorer prognosis of women with ULBC.
Assuntos
Neoplasias da Mama/patologia , Idoso , Feminino , Humanos , Antígeno Ki-67/análise , Pessoa de Meia-Idade , Metástase Neoplásica , Úlcera/patologiaRESUMO
In this study, two different types of amorphous carbonaceous Precambrian rock, classified as noble elite shungite and black raw shungite, were tested as possible electrode materials of natural origin. Both types were machined into cylindrical shapes to form the corresponding solid electrodes and their physicochemical and electrochemical properties were compared with the standard glassy carbon electrode (GCE). The raw stones were first subjected to microscopic imaging by using scanning electron microscopy and energy-dispersive X-ray spectroscopy, both of which indicated significant differences in their morphology and in the content of impurities. An electrode prototype manufactured from noble elite shungite (EShE) with a carbon content of about 94% (w/w) has offered a very satisfactory electrochemical performance with a nearly identical heterogeneous electron-transfer rate constant of 7.8 × 10-3 cm s-1 for ferro/ferricyanide redox couple, a slightly narrower potential range (~2.1 V) and a relatively low double-layer capacitance (of ca. 50 µF), resulting in low background currents comparable to those at the GCE. In contrast, the second electrode based on black raw shungite (BShE) with a carbon content of ca. 63% (w/w) exhibited markedly worse electrochemical properties and more than four times higher double-layer capacitance, both of which were probably due to the presence of poorly conductive impurities. The whole study has been completed with three different examples of electroanalytical applications, revealing that the first type, EShE, is a more suitable material for the preparation of electrodes and may represent a cheap alternative to commercially marketed products.
RESUMO
Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome known as exomphalos-macroglossia - gigantism syndrome. Prognosis is good, prenatal diagnosis is important for pregnancy management but might be difficult due to clinical overlap with other syndromes. Perlman syndrome is an overgrowth syndrome with high perinatal mortality, most frequent antenatal findings include polyhydramnios, macrosomia, visceromegaly, nephromegaly and foetal ascites. Authors present a case of prenatally diagnosed BWS with severe ascites as first antenatal finding and lethal course, signs more typical of Perlman syndrome. This combination of clinical signs has not been published yet and may contribute to specification of possible prenatal manifestation of BWS.