Development and optimisation of novel 68 Ga-folates - towards early diagnosis of ovarian cancer

Der Folsäure-basierte Radiotracer Etarfolatide (99mTc-EC 20) hat in der Vergangenheit sehr vielversprechende Ergebnisse im Bereich der frühzeitigen Diagnostik von Ovarialkarzinomen gezeigt. Einzelphotonen-Emissionscomputertomographie (SPECT) erlaubt dabei eine Visualisierung der Krankheit in einem sehr frühen Stadium – ermöglicht wird dies durch Folsäure, welche als Target Vektor dient. Um das erfolgreiche Prinzip der Radiofolate auf die Positronen-Emissionstomographie (PET) zu übertragen, welche eine noch höhere räumliche Auflösung ermöglicht, wurden in den letzten fünf Jahren bereits 18F-folate entwickelt. Deren hepatobiliären Exkretionsmuster, verursacht durch die relativ hohe Lipophilie der Strukturen, entsprachen jedoch nicht den Anforderungen. Eine optimierte Bioverteilung der Tracer in vivo kann durch eine generelle Erhöhung der Polarität erfolgen. Die Kombination aus einem polaren 68Ga-Komplex mit Folsäure als Target Vektor stellte den Fokus dieses Projektes dar. Ziel war die Entwicklung eines Radiofolates mit der Tendenz einer raschen renalen Ausscheidung und verringerter hepatobiliärer Anreicherung. Dazu wurde Folsäure regiospezifisch über ihre y-Säure an verschiedene bifunktionelle Chelatoren (BFCs) gekoppelt. Vier verschiedene Reaktionstypen wurden gewählt und durchgeführt: Cu-katalysierte sowie Cu-freie Click Reaktion, Amindbindung und Thioharnstoff Bildung. Es wurden sechs verschiedene Derivate erhalten und mit 68Ga radiomarkiert.

Ascorbate is depleted by smoking and repleted by moderate supplementation: a study in male smokers and nonsmokers with matched dietary antioxidant intakes

BACKGROUND: Lack of reliable dietary data has hampered the ability to effectively distinguish between effects of smoking and diet on plasma antioxidant status. As confirmed by analyses of comprehensive food-frequency questionnaires, the total dietary intakes of fruit and vegetables and of dietary antioxidants were not significantly different between the study groups in the present study, thereby enabling isolation of the effect of smoking. OBJECTIVE: Our objective was to investigate the effect of smoking on plasma antioxidant status by measuring ascorbic acid, alpha-tocopherol, gamma-tocopherol, beta-carotene, and lycopene, and subsequently, to test the effect of a 3-mo dietary supplementation with a moderate-dose vitamin cocktail. DESIGN: In a double-blind, placebo-controlled design, the effect of a vitamin cocktail containing 272 mg vitamin C, 31 mg all-rac-alpha-tocopheryl acetate, and 400 microg folic acid on plasma antioxidants was determined in a population of smokers (n = 37) and nonsmokers (n = 38). The population was selected for a low intake of fruit and vegetables and recruited from the San Francisco Bay area. RESULTS: Only ascorbic acid was significantly depleted by smoking per se (P < 0.01). After the 3-mo supplementation period, ascorbic acid was efficiently repleted in smokers (P < 0.001). Plasma alpha-tocopherol and the ratio of alpha- to gamma-tocopherol increased significantly in both supplemented groups (P < 0.05). CONCLUSIONS: Our data suggest that previous reports of lower concentrations of plasma vitamin E and carotenoids in smokers than in nonsmokers may primarily have been caused by differences in dietary habits between study groups. Plasma ascorbic acid was depleted by smoking and repleted by moderate supplementation.

Epidemiological survey of 214 families with bladder exstrophy-epispadias complex

PURPOSE: We sought to identify causative nongenetic and genetic risk factors for the bladder exstrophy-epispadias complex. MATERIALS AND METHODS: A total of 237 families with the bladder exstrophy-epispadias complex were invited to participate in the study, and information was obtained from 214 families, mainly from European countries. RESULTS: Two families showed familial occurrence. Male predominance was found among all subgroups comprising epispadias, classic bladder exstrophy and cloacal exstrophy, with male-to-female ratios of 1.4:1, 2.8:1 and 2.0:1, respectively (p = 0.001). No association with parental age, maternal reproductive history or periconceptional maternal exposure to alcohol, drugs, chemical noxae, radiation or infections was found. However, periconceptional maternal exposure to smoking was significantly more common in patients with cloacal exstrophy than in the combined group of patients with epispadias/classic bladder exstrophy (p = 0.009). Only 16.8% of mothers followed the current recommendations of periconceptional folic acid supplementation, and 17.6% had started supplementation before 10 weeks of gestation. Interestingly, in the latter group mothers of patients with cloacal exstrophy were more compliant with folic acid supplementation than were mothers of the combined group of patients with epispadias/classic bladder exstrophy (p = 0.037). Furthermore, mothers of children with cloacal exstrophy knew significantly more often prenatally that their child would have a congenital malformation than did mothers of children with epispadias/classic bladder exstrophy (p <0.0001). CONCLUSIONS: Our study corroborates the hypothesis that epispadias, classic bladder exstrophy and cloacal exstrophy are causally related, representing a spectrum of the same developmental defect, with a small risk of recurrence within families. Embryonic exposure to maternal smoking appears to enforce the severity, whereas periconceptional folic acid supplementation does not seem to alleviate it. There is a disproportional prenatal ultrasound detection rate between severe and mild phenotypes, possibly due to the neglect of imaging of full bladders with a focus on neural tube defects.

Lifestyle and stroke risk: a review

PURPOSE OF REVIEW: In recent years, many epidemiological studies have given new insights into old and new lifestyle factors that influence the risk of cerebrovascular events. In this review, we refer to the most important articles to highlight recent advances, especially those important for stroke prevention. RECENT FINDINGS: This review focuses on the most recent studies that show the association of environmental factors, nutrition, alcohol, tobacco, education, lifestyle and behavior with the risk of vascular disease, including ischemic stroke and cerebral hemorrhage. The link between air pollution and stroke risk has become evident. Low education levels and depression are established as risk factors. This is also true for heavy alcohol consumption, although moderate drinking may be protective. Active and passive smoking are independent risk factors, and a smoking ban in public places has already reduced cardiovascular events in the short term. Physical activity reduces stroke risk; overweight increases it. However, clinical trials to assess the effect of weight reduction on stroke risk are still lacking. Fruits, vegetables, fish, fibers, low-fat dairy products, potassium and low sodium consumption are known and recommended to reduce cardiovascular risk. Data on omega 3 fatty acid, folic acid and B vitamins are inconsistent, and antioxidants are not recommended. SUMMARY: Stroke can be substantially reduced by an active lifestyle, cessation of smoking and a healthy diet. Both public and professional education should promote the awareness that a healthy lifestyle and nutrition have the potential to reduce the burden of stroke.

Prevalence of anaemia in inflammatory bowel disease in Switzerland: A cross-sectional study in patients from private practices and university hospitals

BACKGROUND: Anaemia represents a common complication of inflammatory bowel disease (IBD). Most studies on anaemia in IBD patients have been performed in tertiary referral centres (RC) and data from gastroenterologic practices (GP) are lacking. We investigated the frequency and severity of anaemia in IBD patients from tertiary referral centres and gastroenterologic practices compared to the general population. METHODS: Data were acquired from patients included in the Swiss IBD Cohort Study. IBD activity was evaluated by CDAI and modified Truelove and Witts severity index (MTWSI). Anaemia was defined as haemoglobin ≤120g/L in women and ≤130g/L in men. RESULTS: 125 patients from RC (66 with Crohn's disease (CD) and 59 with ulcerative colitis (UC)) and 116 patients from GP (71 CD and 45 UC) were included and compared to 6074 blood donors. Anaemia was found in 21.2% (51/241) of the IBD patients and more frequently in patients from RC as compared to GP and healthy controls (28.8% vs. 12.9% vs. 3.4%; P<0.01). IBD patients from RC suffered more frequently from active disease compared to IBD patients in GP (36% vs. 23%, P=0.032). Supplementation therapy (iron, vitamin B12, folic acid) was performed in 40% of anaemic IBD patients in GP as compared to 43% in RC. CONCLUSIONS: Anaemia is a common complication in patients with IBD and significantly more prevalent in patients from referral centres as compared to patients from gastroenterologic practices. Physicians treating IBD patients should pay attention to the presence of anaemia and ensure sufficient supplementation therapy.

Association of folate receptor (FOLR1, FOLR2, FOLR3) and reduced folate carrier (SLC19A1) genes with meningomyelocele.

BACKGROUND: Meningomyelocele (MM) results from lack of closure of the neural tube during embryologic development. Periconceptional folic acid supplementation is a modifier of MM risk in humans, leading toan interest in the folate transport genes as potential candidates for association to MM. METHODS: This study used the SNPlex Genotyping (ABI, Foster City, CA) platform to genotype 20 single polymorphic variants across the folate receptor genes (FOLR1, FOLR2, FOLR3) and the folate carrier gene (SLC19A1) to assess their association to MM. The study population included 329 trio and 281 duo families. Only cases with MM were included. Genetic association was assessed using the transmission disequilibrium test in PLINK. RESULTS: A variant in the FOLR2 gene (rs13908), three linked variants in the FOLR3 gene (rs7925545, rs7926875, rs7926987), and two variants in the SLC19A1 gene (rs1888530 and rs3788200) were statistically significant for association to MM in our population. CONCLUSION: This study involved the analyses of selected single nucleotide polymorphisms across the folate receptor genes and the folate carrier gene in a large population sample. It provided evidence that the rare alleles of specific single nucleotide polymorphisms within these genes appear to be statistically significant for association to MM in the patient population that was tested.

Juvenile onset central nervous system folate deficiency and rheumatoid arthritis.

Isolated cerebral folate deficiency was detected in a 13-year-old girl with cognitive and motor difficulties and juvenile rheumatoid arthritis. Her serum contains autoantibodies that block membrane-bound folate receptors that are on the choroid plexus and diminish the uptake of folate into the spinal fluid. Whereas her serum folate exceeded 21 ng/mL, her spinal fluid contained 3.2 ng/mL of 5-methyltetrahydrofolate as a consequence of the autoantibodies diminishing the uptake of this folate.

Evaluation of Recurrence Risks for Left-Sided Cardiac Lesions

It is widely accepted that hypoplastic left heart syndrome (HLHS), aortic valve stenosis with or without bicuspid aortic valve (AS/BAV) and coarctation of the aorta (CoA) occur in families more commonly with each other than with any other congenital heart defect (CHD). Genetic counseling for CHDs is currently based on empiric risk estimates derived from data collected on all types of CHDs between 1968 and 1990. Additionally, for the specific group of defects described above, termed left-sided lesions, estimates are available for sibling recurrence. Utilizing family history data from 757 probands recruited between 1997 and 2007 from The Children’s Hospital of Philadelphia, this study reassessed the pre/recurrence risks for LSLs specifically. Sibling pre/recurrence risks for HLHS (5.5%, 95% CI: 3.1%-8.9%), CoA (4.0%, 95% CI: 2.1%-6.7%), and AS/BAV (6.0%, 95% CI: 3.3%-9.8%) were higher than currently quoted risks based on sibling data for individual LSLs. Additionally, the prevalence of BAV in 202, apparently unaffected, parents of 134 probands was assessed by echocardiography. BAV, which occurs at a frequency of 1% in the general population, was found to occur in approximately 10% of parents of LSL probands. Lastly, among affected first-degree relative pairs (i.e. siblings, parent-offspring), the majority (65%-70%) were both affected with a LSL. Defect specific concordance rates were highest for AS/BAV. Together, these findings suggest that over the past 20 years with changing diagnostic capabilities and environmental/maternal conditions (e.g. folic acid fortification, increased maternal diabetes and obesity) recurrence risks may have increased, as compared to current LSL specific risk estimates. Based on these risk estimate increases and prior studies, a protocol for screening first-degree relatives of LSL probands should be devised.

Functional studies of homeobox gene {\it Cart1\/} during mouse development

Cart1 is a paired-class homeobox-containing gene that is expressed in head mesenchyme, branchial arches, limb buds, and various cartilages during embryogenesis. To understand the role of Cart1 during mammalian development, I generated Cart1-mutant mice by gene targeting in mouse embryonic stem cells. Cart1-homozygous mutants were born alive but all died soon after birth. Most had acrania (absence of the cranial vault) and meroanencephaly (absence of part of the brain). In situ hybridization studies showed that Cart1 is expressed specifically in forebrain mesenchyme but not in midbrain or hindbrain mesenchyme nor in the neural tube. Developmental studies revealed a transient deficiency of forebrain mesenchyme cells due to apoptosis associated with a delay in neural tube closure in that region. Subsequently, the forebrain region became filled with mesenchyme and closed, however, the midbrain neural tube region never initiated closure and remained open. These results suggest that Cart1 is required for the survival of forebrain mesenchyme and that its absence disrupts cranial neural tube morphogenesis by blocking the initiation of closure in the midbrain region, and this ultimately leads to the generation of lethal craniofacial defects. Prenatal treatment of Cart1 homozygous mutants with folic acid suppressed the development of the acrania/meroanencephaly phenotype. Thus, Cart1 mutant mice provide a novel animal model for understanding the cellular, molecular, and genetic etiology of neural tube defects and for the development of prenatal therapeutic protocols using folic acid. ^

Improving the health and well-being of women at risk for neural tube defect recurrence

There is growing interest in providing women with internatal care, a package of healthcare and ancillary services that can improve their health during the period after the termination of one pregnancy but before the conception of the next pregnancy. Women who have had a pregnancy affected by a neural tube defect can especially benefit from internatal care because they are at increased risk for recurrence and improvements to their health during the inter-pregnancy period can prevent future negative birth outcomes. The dissertation provides three papers that inform the content of internatal care for women at risk for recurrence by examining descriptive epidemiology to develop an accurate risk profile of the population, assessing whether women at risk for recurrence would benefit from a psychosocial intervention, and determining how to improve health promotion efforts targeting folic acid use.^ Paper one identifies information relevant for developing risk profiles and conducting risk assessments. A number of investigations have found that the risk for neural tube defects differs between non-Hispanic Whites and Hispanics. To understand the risk difference, the descriptive epidemiology of spina bifida and anencephaly was examined for Hispanics and non-Hispanic Whites based on data from the Texas Birth Defects Registry for the years 1999 through 2004. Crude and adjusted birth prevalence ratios and corresponding 95% confidence intervals were calculated between descriptive epidemiologic characteristics and anencephaly and spina bifida for non-Hispanic Whites and for Hispanics. In both race/ethnic groups, anencephaly expressed an inverse relationship with maternal age and a positive linear relationship with parity. Both relationships were stronger in non-Hispanic Whites. Female infants had a higher risk for anencephaly in non-Hispanic Whites. Lower maternal education was associated with increased risk for spina bifida in Hispanics.^ Paper two assesses the need for a psychosocial intervention. For mothers who have children with spina bifida, the transition to motherhood can be stressful. This qualitative study explored the process of becoming a mother to a child with spina bifida focusing particularly on stress and coping in the immediate postnatal environment. Semi-structured interviews were conducted with six mothers who have children with spina bifida. Mothers were asked about their initial emotional and problem-based coping efforts, the quality and kind of support provided by health providers, and the characteristics of their meaning-based coping efforts; questions matched Transactional Model of Stress and Coping (TMSC) constructs. Analysis of the responses revealed a number of modifiable stress and coping transactions, the most salient being: health providers are in a position to address beliefs about self-causality and prevent mothers from experiencing the repercussions that stem from maintaining these beliefs. ^ Paper three identifies considerations when creating health promotion materials targeting folic acid use. A brochure was designed using concepts from the Precaution Adoption Process Model (PAPM). Three focus groups comprising 26 mothers of children with spina bifida evaluated the brochure. One focus group was conducted in Spanish-only, the other two focus groups were conducted in English and Spanish combined. Qualitative analysis of coded transcripts revealed that a brochure is a helpful adjunct. Questions about folic acid support the inclusion of an insert with basic information. There may be a need to develop different educational material for Hispanics so the importance of folic acid is provided in a situational context. Some participants blamed themselves for their pregnancy outcome which may affect their receptivity to messages in the brochure. The women's desire for photographs that affect their perception of threat and their identification with the second role model indicate they belong to PAPM Stage 2 and 3. Participants preferred colorful envelopes, high quality paper, intimidating photographs, simple words, conversational style sentences, and positive messages.^ These papers develop the content of risk assessment, psychosocial intervention, and health promotion components of internatal care as they apply to women at risk for recurrence. The findings provided evidence for considering parity and maternal age when assessing nutritional risk. The two dissimilarities between the two race/ethnic groups, infant sex and maternal education lent support to creating separate risk profiles. Interviews with mothers of children with spina bifida revealed the existence of unmet needs-suggesting that a psychosocial intervention provided as part of internatal care can strengthen and support women's well-being. Segmenting the audience according to race/ethnicity and PAPM stage can improve the relevance of print materials promoting folic acid use.^

A systematic review of selected birth outcomes in diabetic women who received preconception care and/or used multivitamins prior to pregnancy

Objective. To conduct a systematic review of published literature on preconception care in pre-existing diabetic women looking at the effect of glycemic control and multivitamin usage on the frequency of spontaneous abortion and birth defects.^ Methods. Articles were retrieved from Medline (1950–Dec 2007), Cochrane Library (1800–Dec 2007), Academic Search Complete (Ebsco) (Jan 1800–Dec 2007) and Maternal and Child Health Library (1965–Dec 2007). Studies included women with pre-existing, non-gestational diabetes and a comparison group. Participants must have either received preconception care and/or consumed a multivitamin as part of the study.^ Results. Overall, seven studies met the study criteria and applicability to the study objectives. Four of these reported the frequency of spontaneous abortion. Only one found a statistically significant increased risk of spontaneous abortion among pregnant women who did not receive preconception care compared with those who did receive care, odds ratio 4.32; 95% CI 1.34 to 13.9. Of the seven studies, six reported the frequency of birth defects. Five of these six studies found a significantly increased rate of birth defects among pregnant women who did not receive preconception care compared with those who did receive care, with odds ratios ranging from 1.53 to 10.16. All seven studies based their preconception care intervention on glycemic control. One study also used multivitamins as part of the preconception care.^ Conclusion. Glycemic control was shown to be useful in reducing the prevalence of birth defects, but not as useful in reducing the prevalence of spontaneous abortion. Insulin regimen options vary widely for the diabetic woman. No author excluded or controlled for women who may have been taking a multivitamin on their own. Due to the small amount of literature available, it is still not known which preconception care option, glucose control and/or multivitamin usage, provides better protection from birth defects and spontaneous abortion for the diabetic woman. An area for future investigation would be glycemic control and the use of folic acid started before pregnancy and the effects on birth defects and spontaneous abortion.^

Better together: Addressing maternal and child health outcomes through community health worker continuing education curricula

Background. The incidence of birth defects is a significant public health issue in the United States, adversely affecting the quality of life for parents as well as children born with these defects. Minority populations face a greater burden of birth defects and associated health problems. Prenatal practices can have a large impact on infant health outcomes. Several behaviors during pregnancy, including the intake of folic acid, can greatly influence the likelihood of a child being born with a birth defect. Community Health Workers have been shown to be effective agents at improving prenatal practices, especially when they facilitate support groups that feature pregnant women. ^ Methods. A continuing education curriculum has been created for Community Health Workers that provides content in the area of Maternal and Child Health. Content was selected after conducting a review of relevant literature and theory. Materials for conducting a training for Community Health Workers have been created in addition to materials that were designed for the population with whom the CHWs work. ^ Results. A description of each "key point" of the curriculum and a justification how it relates to the literature of the prevention of birth defects is given here. Additionally, the process of creating the curriculum using the platform delineated in the methods is described. ^ Discussion. Insights for future curriculum development are discussed along with next steps in the process of certifying the curriculum at the state level. A framework for future evaluation of the curriculum is given.^

Prevention of birth defects in a national study

The following analyses covered two main objectives focused on the prevention of and identification of risk factors for birth defects, the leading cause of infant mortality. All analyses utilized data from the National Birth Defects Prevention Study (NBDPS), an ongoing, population-based, case-control study of major structural birth defects. ^ The first objective was to identify predictors of folic acid supplementation among women of reproductive age. To meet this objective, a previous analysis of potential predictors of periconcecptional folic acid use in the NBDPS was repeated using data from more recent years (1997-2000 versus 2001-2005). The results of these analyses were consistent with the initial analyses, indicating that folic acid use is associated with maternal race/ethnicity, age, education, pregnancy awareness, smoking status, first prenatal care visit, previous live births, and fertility treatments). In addition, data from NBDPS controls were used to identify predictors of preconceptional folic acid use, since supplementation is optimally initiated prior to pregnancy (rather than after conception). These analyses indicated that maternal race/ethnicity, education, age, nativity, employment status, income, number of dependents, smoking, and birth control are significantly associated with preconceptional folic acid supplementation. Ultimately the results of these analyses can be used to guide the development of targeted interventions for preconceptional folic acid use. ^ The second objective was to investigate the association between parental Hispanic acculturation and the risk of gastroschisis, a congenital malformation of the abdominal wall, in offspring. Significant association were not observed for mothers < 20 years of age at conception. Among mothers ≥ 20 years of age, white parents were at a decreased risk of having a child with gastroschisis as compared to Hispanic parents who were born in the United States (US) [odd ratios (ORs) ranging from 0.60 to 0.55] and Hispanics parents who predominantly spoke English (ORs ranging from 0.65 to 0.58). Compared to Hispanic mothers born in the US, the risk of gastroschisis was lower among Hispanic mothers who had lived in the US < 5 years (OR=0.36, 95% CI: 0.42, 0.81) at the time of delivery and Hispanic mothers who migrated to the US at ≥ 20 years of age (OR=0.48, 95% CI: 0.26, 0.89). The results of these analyses provide further evidence that the risk of gastroschisis in offspring is associated with parent Hispanic ethnicity and, among Hispanics, with the degree of parental acculturation. Future studies should focus on characteristic differences between less and more acculturated parents to better understand the relationship between acculturation and gastroschisis.^

Selective killing of preneoplastic and neoplastic cells by methotrexate with leucovorin

Three sublines of NIH 3T3 cells had the properties of non-neoplastic, preneoplastic, and neoplastic cells, respectively. The closer the cells were to neoplastic behavior, characterized by continuing growth at high density, the slower they multiplied at lower density. Under the conditions of high population density and low calf serum concentration used in the assay for transformed focus formation, the transformed or neoplastic cells were much more sensitive to killing by methotrexate (MTX) than were non-neoplastic cells in the same culture. This differential sensitivity of neoplastic cells was far more pronounced in molecular, cellular, and developmental biology medium 402 (MCDB 402) than in DMEM. It is associated with the presence in MCDB 402 of folinic acid, known clinically as leucovorin, which is a reduced form of the folic acid present in DMEM. Although leucovorin had been shown to selectively spare normal bone marrow and intestine in animals from the killing effect of MTX on tumor cells, we demonstrate the preferential killing of neoplastic over non-neoplastic cells of the same derivation. Neither neoplastic nor non-neoplastic cells were killed once they had stopped multiplying at their respective saturation densities. The development of the light foci characteristic of the preneoplastic cells was less sensitive to MTX than the formation of the dense foci produced by the fully neoplastic cells. The system should serve as a valuable model to establish basic principles and optimal conditions for selective killing of neoplastic cells by chemotherapeutic drugs.

Caracterização e aplicação analítica de eletrodos modificados com sistemas porfirínicos supramoleculares

Estudos com eletrodos modificados foram conduzidos utilizando dois sistemas porfirínicos supramoleculares diferentes. O primeiro foi baseado na modificação de eletrodo de carbono vítreo com uma porfirina de níquel tetrarrutenada, [NiIITPyP{RuII(bipy)2Cl}4]4+. A modificação do eletrodo foi realizada por meio de sucessivos ciclos voltamétricos em meio alcalino (pH 13), gerando um eletrodo com característica similar a eletrodos modificados com α-Ni(OH)2. A caracterização química do filme formado foi realizada através das técnicas de voltametria cíclica, ressonância paramagnética eletrônica, espectroscopia eletrônica por reflectância e espectroscopia Raman com ensaio espectro-eletroquímico. Os resultados sugerem a formação de um polímero de coordenação, [µ-O2-NiIITPyP{RuII(bipy)2Cl}4]n, composto por subunidades porfirínicas ligadas entre si por pontes µ-peroxo axialmente coordenadas aos átomos de níquel (Ni-O-O-Ni). O crescimento do filme apresentou dependência da alcalinidade do meio pela formação do precursor octaédrico [Ni(OH)2TRPyP]2+ em solução, pela coordenação de OH- nas posições axiais do átomo de níquel. O processo de eletropolimerização indicou a participação de radical hidroxil, gerado por oxidação eletrocatalítica da água nos sítios periféricos da porfirina contendo o complexo de rutênio. O mesmo eletrodo foi aplicado como sensor eletroquímico para análise amperométrica de ácido fólico em comprimidos farmacêuticos. O sensor foi associado a um sistema de Batch Injection Analysis (BIA) alcançando considerável rapidez e baixo limite de detecção. Para as análises das amostras também foi proposto um método para a remoção da lactose, que agia como interferente. O segundo estudo envolveu a modificação de eletrodos de carbono vítreo com diferentes hemoglobinas, naturais (HbA0, HbA2 e HbS) e sintéticas (Hb-PEG5K2, αα-Hb-PEG5K2 e BT-PEG5K4), para a avaliação da eficiência na redução eletrocatalítica de nitrito mediada por FeI-heme. Os filmes foram produzidos pela mistura de soluções das hemoglobinas com brometo de didodecildimetiltrimetilamônio (DDAB), aplicados nas superfícies com consecutiva evaporação, formando filmes estáveis. Os valores de potencial redox para os processos do grupo heme e a sua associação com a disponibilidade do grupo na proteína foram avaliados por voltametria cíclica. Os valores das constantes de velocidade, k, para redução de nitrito foram obtidos por cronoamperometria em -1,1 V (vs Ag/AgCl(KCl 3M)) que foram utilizados para estudo comparativo entre as espécies sintéticas para eventual aplicação clínica.