Pregnancy in women undergoing hemodialysis: case series in a Southeast Brazilian reference center / Gestação em mulheres em tratamento hemodialítico: série de casos em um centro de referência do Sudeste do Brasil

PURPOSE: To describe maternal and neonatal outcomes in pregnant women undergoing hemodialysis in a referral center in Brazilian Southeast side. METHODS: Retrospective and descriptive study, with chart review of all pregnancies undergoing hemodialysis that were followed-up at an outpatient clinic of high- risk prenatal care in Southeast Brazil. RESULTS: Among the 16 women identified, 2 were excluded due to follow-up loss. In 14 women described, hypertension was the most frequent cause of chronic renal failure (half of cases). The majority (71.4%) had performed hemodialysis treatment for more than one year and all of them underwent 5 to 6 hemodialysis sessions per week. Eleven participants had chronic hypertension, 1 of which was also diabetic, and 6 of them were smokers. Regarding pregnancy complications, 1 of the hypertensive women developed malignant hypertension (with fetal growth restriction and preterm delivery at 29 weeks), 2 had acute pulmonary edema and 2 had abruption placenta. The mode of delivery was cesarean section in 9 women (64.3%). All neonates had Apgar score at five minutes above 7. CONCLUSIONS: To improve perinatal and maternal outcomes of women undergoing hemodialysis, it is important to ensure multidisciplinary approach in referral center, strict control of serum urea, hemoglobin and maternal blood pressure, as well as close monitoring of fetal well-being and maternal morbidities. Another important strategy is suitable guidance for contraception in these women. .

OBJETIVOS: Descrever os resultados maternos e neonatais de mulheres grávidas que estavam em tratamento de hemodiálise em um centro de referência no Sudeste brasileiro. MÉTODOS: Estudo retrospectivo e descritivo, com revisão de prontuários de todas as gestações em hemodiálise, acompanhadas no pré-natal especializado da região Sudeste do Brasil. RESULTADOS: Entre as 16 mulheres identificadas, 2 foram excluídas devido à perda de seguimento. Das 14 descritas, a hipertensão foi a causa mais frequente de insuficiência renal crônica (50% dos casos). A maioria (71,4%) realizava tratamento de hemodiálise há mais de um ano e todas elas foram submetidas a 5 ou 6 sessões por semana. Onze mulheres tinham hipertensão crônica, 1 das quais também era diabética, e 6 eram fumantes. Em relação às complicações da gravidez, 1 das mulheres hipertensas desenvolveu hipertensão maligna (com restrição de crescimento fetal e parto prematuro com 29 semanas), 2 tiveram edema pulmonar agudo e 2 apresentaram descolamento prematuro de placenta. O tipo de parto foi cesariana em 9 mulheres (64,3%). Todos os recém-nascidos tiveram Apgar aos cinco minutos maior que 7. CONCLUSÕES: Para melhorar os resultados perinatais e maternos de mulheres em hemodiálise, é importante ter uma abordagem multidisciplinar em centro de referência, um controle rigoroso da uremia, hemoglobina e pressão arterial materna, bem como acompanhar de perto o bem-estar fetal e a morbidade materna. Outra estratégia importante é a orientação adequada para contracepção nessas mulheres. .

Biochemical characterization of the bifunctional enzyme dihydrofolate reductase-thymidylate synthase from Leishmania ( Viannia ) and its evaluation as a drug target / Caracterización bioquímica de la enzima bifuncional dihidrofolato reductasa-timidilato sintasa de Leishmania ( Viannia ) y su evaluación como blanco molecular

Introduction. Dihydrofolate reductase (DHFR) has been used successfully as a drug target in the area of anti-bacterial, anti-cancer and anti-malarial therapy. Although this bifunctional enzyme is also a potential drug target for treatment of leishmaniasis, there have been no reports on its efficacy against Leishmania ( Viannia ) species . Materials and methods. The gene encoding the bifunctional DHFR and thymidylate synthase (TS) of Le. (V.) braziliensis was isolated and expressed in E. coli. The enzyme was purified and characterized. The inhibitory effects of antifolates and four aporphine alkaloids on its activity were evaluated. Results. The full-length gene consists of a 1560-bp open reading frame encoding a 58 kDa translated peptide containing DHFR and TS domains linked together in a single polypeptide chain. The recombinant DHFR-TS enzyme revealed K m and V max values of 55.35 ± 4.02 µ M (mean ± SE) and 0.02 ± 5.34 x 10 -4 µ M/min respectively for dihydrofolic acid (H 2 F). The Le. braziliensis rDHFR-TS have Ki values for antimicrobial antifolates in the µM range. Methotrexate (MTX) was a more-potent inhibitor of enzymatic activity ( Ki = 22.0 µM) than trimethoprim ( Ki = 33 µM) and pyrimethamine ( Ki = 68 µM). These Ki values are significantly lower than those obtained for the aporphine alkaloids. Conclusion. The results of the study show the inhibitory effect of antifolate drugs on enzymatic activity, indicating that Le. braziliensis rDHFR-TS could be a model to studying antifolate compounds as potential antiprotozoal drugs.

Introducción. La dihidrofolato reductasa (DHFR) se ha utilizado como blanco molecular en tratamientos antibacterianos, anticancerígenos y antipalúdicos. También, actúa como blanco molecular en Leishmania ; sin embargo, no existen reportes de la enzima bifuncional en especies de Leishmania ( Viannia ). Materiales y métodos. Se ha aislado y expresado en Escherichia coli el gen que codifica para la enzima bifuncional DHFR y la timidilato-sintasa (TS) de Leishmania braziliensis . La enzima recombinante se purificó y caracterizó, y se evaluó el efecto inhibitorio de algunos antifolatos, así como de cuatro alcaloides aporfínicos. Resultados. El gen se compone de aproximadamente 1.560 pb y codifica un péptido de 58 kDa que contiene los dominios DHFR y TS ligados en una sola cadena polipeptídica. La enzima recombinante DHFR-TS, utilizando el dihidrofolato (H2F) como sustrato, presentó valores de K m y V max de 55,35 ± 4,02 (media ± el error estándar de la media) y de 0,02 ± 5,34 x 10 -4 , respectivamente. La enzima rDHFR-TS de L. braziliensis presentó valores de Ki para los antifolatos en el rango de micras. El metotrexato fue el inhibidor más potente de la actividad enzimática ( Ki =22,0 mM) en comparación del trimetoprim ( Ki =33 mM) y la pirimetamina ( Ki =68 mM). Estos valores de Ki son significativamente más bajos en comparación con los obtenidos para los alcaloides aporfínicos. Conclusión. Los resultados muestran el efecto inhibitorio de los antifolatos sobre la actividad enzimática, lo cual indica que la rDHFR-TS de L. braziliensis podría ser un modelo para estudiar moléculas antiprotozoarias potenciales.

retrospective comparison of concurrent bolus 5-fluorouracil or raltitrexed in preoperative chemoradiation for locally advanced rectal cancer

5-fluorouracil [FU] is commonly used in preoperative chemoradiation in locally advanced rectal cancer, but not all patients cooperate in taking the 5-day continuous infusion regimen. Raltitrexed [RA], a thymidylate synthase inhibitor, is one of the agents used in place of FU in such cases. We retrospectively compared the toxicity, tumor downstaging, pathologic response and relapse rate with bolus FU or RA during concurrent radiotherapy [RT] to assess the role of RA in place of FU. We conducted a retrospective analysis of response rates and toxicity data on 59 patients diagnosed with locally advanced rectal cancer and treated with surgery following preoperative chemoradiation with either concurrent FU or RA between January 1999 and December 2004. Median follow-up was 38 months [range, 1-70]. Ten patients [10%] had grade 3 gastrointestinal [GIS] toxicity during chemoradiation. The pathologic complete response rates were 6% with FU and 7% with RA [P=0.844], while 66.7% of patients treated with FU and 37.1% with RA had downstaging of the T stage after chemoradiation [P=0.026]. The sphincter preservation rates were 45.8% with FU and 51.4% with RA [P=0.912]. The 5-year local control rates were 79.2% for patients treated with RT+FU and 85.76% for patients treated with RT+RA [P=0.510]. Compared with the RT+RA regimen, the incidence of downstaging was greater with RT+FU but RT+FU was associated with a correspondingly greater rate of acute grade 2 GIS toxicity. However, no significant differences were seen in sphincter preservation, pathologic complete response, local control and distant recurrences rates among patients. FU seems to be the best therapeutic choice, while RA seems to be as effective as bolus FU

Second line chemotherapy in locally advanced or metastatic non-small-cell lung cancer

Most of the patients affected with locally advanced non-small-cell lung cancer have a recurrence or an evolutionary resumption of their disease justifying a second line treatment. The docetaxel gives a significant survival benefit, compared with palliative care. Several trials were reported with gemcitabine, vinorelbine, and paclitaxel. Pemetrexed shows a survival benefit similar to that docetaxel but with less side effects. Many other treatments have been evaluated lately, especially those with targeted molecules

Inhibition of thymidylate synthase by pergularinine, tylophorinidine and deoxytubulosine.

The activity of thymidylate synthase (TS) purified in our laboratory from Lactobacillus leichmannii was inhibited by pergularinine (PGL) and tylophorinidine (TPD) and deoxytubulosine (DTB) isolated from the Indian medicinal plants Pergularia pallida and Alangium lamarckii respectively. Cytotoxicity studies showed that cell growth of L. leichmannii was inhibited (IC50 = 40-45 microM) by all the three alkaloids, the concentrations > 80-90 microM resulting in complete loss of the enzyme activity. Ki values of the enzyme calculated from Lineweaver-Burk and Dixon plots for PGL, TPD and DTB were 10 x 10(-6) M, 9 x 10(-6) M and 7 x 10(-6) M respectively. These are typed as 'non-competitive' inhibitors of TS. All the three alkaloids inhibited (IC50 = 50 microM) the elevated TS activity of leukocytes in cancer patients with clinically diagnosed chronic myelocytic leukemia (n = 10), acute lymphocytic leukemia (n = 8) and metastatic solid tumours (n = 3).

Reversible inhibition by pyridoxal 5'-phosphate and irreversible inactivation by urea and guanidine hydrochloride of thymidylate synthase from Lactobacillus leichmannii.

Pyridoxal 5'-phosphate reversibly inhibited thymidylate synthase from Lactobacillus leichmannii. The inhibition was competitive with dUMP (Ki = 1 microM) and non-competitive with 5,10-CH2-THF (Ki = 0.08 microM). Treatment of native or pCMB-treated enzyme with urea (5 M) or guanidine hydrochloride (4 M) resulted in inactivation and dissociation of the homodimer (74 kDa) into monomer (37 kDa).

Ternary complex formation with 5-fluoro-2'-deoxyuridylate and the kinetic properties of thymidylate synthase from Lactobacillus leichmannii.

Lactobacillus leichmannii thymidylate synthase (5,10-CH2-H4PteGlu:dUMP C-methyltransferase, EC 2.1.1.45) forms a tight and stable covalently bonded ternary complex with the inhibitor 5-FdUMP in the presence of the cofactor 5,10-CH2-H4-PteGlu. 'Filter assay' employing the radioactive nucleotide ligand showed that 2 moles of FdUMP are bound per mole enzyme during the ternary complex formation with the L. leichmannii dTMP synthase. This is in line with our earlier observation on the Streptococcus faecium thymidylate synthase [Narasimha Rao, K & Kisliuk R L (1983), Proc Natl Acad Sci USA, 80, 916-920]. The enzyme has Km values of 6.3 x 10(-6) M, 8.2 x 10(-5) M and 1.0 x 10(-4) M for dUMP, (dl)-L-H4PteGlu and Mg2+ respectively; Vmax for dUMP, (dl)-L-H4PteGlu and Mg2+ are; 0.55, 0.5 and 1.1 respectively. It has K(i) values of 6.7 x 10(-6) M, 2.2 x 10(-6) M, 5.0 x 10(-5) M and 2.0 x 10(-4) M for FdUMP, dTMP, MTX and Ca2+ respectively. The type of enzyme inhibition with FdUMP, dTMP, MTX and Ca2+ was competitive. dTMP Studies clearly show the 'end product' inhibition of the enzyme.