958 resultados para Aromatic substitution


Relevância:

20.00% 20.00%

Publicador:

Resumo:

PURPOSE: In male patients with ileal bladder substitute we ascertained the likelihood of spontaneous voiding failure, the corrective procedures required and the eventual outcomes. MATERIALS AND METHODS: Following cystectomy and ileal bladder substitution for urothelial cancer between April 1985 and September 2002 male patients were identified and analyzed from the prospective departmental database. Four patients underwent ileum conduit conversion following urethral recurrence or pouch necrosis and were excluded from study. Funnel-shaped outlets were avoided during bladder substitute surgery after the first 4 patients with this configuration experienced voiding failure and required corrective procedures. Only patients with a minimum 5-year followup were assessed for voiding failure, corrective procedures and final outcomes. RESULTS: Of 354 patients with a median age of 65 years (range 36 to 84) treated with bladder substitute 180 (51%) were alive at 5 years. All 180 of these patients spontaneously voided within 3 months of surgery. During this 5-year observation period 22 (12%) patients experienced voiding problems requiring de-obstructive procedures. Following intervention 177 (98%) patients were spontaneously voiding by 5 years. Of 237 patients 77 (32%) were alive at 10 years. Of these 77 patients followed for another 5 years 10 (13%) had similar voiding problems requiring de-obstructive procedures. Subsequently 74 (96%) were voiding spontaneously by 10 years. CONCLUSIONS: Patients often fail to void spontaneously after ileal bladder substitution. However, if a funnel-shaped outlet is avoided and de-obstructive surgery is appropriately implemented, excellent long-term results are seen with spontaneous voiding and clean intermittent catheterization can be avoided.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recently, a novel group of fungal peroxidases, known as the aromatic peroxygenases (APO), has been discovered. Members of these extracellular biocatalysts produced by agaric basidiomycetes such as Agrocybe aegerita or Coprinellus radians catalyze reactions--for example, the peroxygenation of naphthalene, toluene, dibenzothiophene, or pyridine--which are actually attributed to cytochrome P450 monooxygenases. Here, for the first time, genetic information is presented on this new group of peroxide-consuming enzymes. The gene of A. aegerita peroxygenase (apo1) was identified on the level of messenger RNA and genomic DNA. The gene sequence was affirmed by peptide sequences obtained through an Edman degradation and de novo peptide sequencing of the purified enzyme. Quantitative real-time reverse transcriptase polymerase chain reaction demonstrated that the course of enzyme activity correlated well with that of mRNA signals for apo1 in A. aegerita. The full-length sequences of A. aegerita peroxygenase as well as a partial sequence of C. radians peroxygenase confirmed the enzymes' affiliation to the heme-thiolate proteins. The sequences revealed no homology to classic peroxidases, cytochrome P450 enzymes, and only little homology (<30%) to fungal chloroperoxidase produced by the ascomycete Caldariomyces fumago (and this only in the N-terminal part of the protein comprising the heme-binding region and part of the distal heme pocket). This fact reinforces the novelty of APO proteins. On the other hand, homology retrievals in genetic databases resulted in the identification of various APO homologous genes and transcripts, particularly among the agaric fungi, indicating APO's widespread occurrence in the fungal kingdom.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Agrocybe aegerita peroxidase/peroxygenase (AaP) is an extracellular fungal biocatalyst that selectively hydroxylates the aromatic ring of naphthalene. Under alkaline conditions, the reaction proceeds via the formation of an intermediary product with a molecular mass of 144 and a characteristic UV absorption spectrum (A(max) 210, 267, and 303 nm). The compound was semistable at pH 9 but spontaneously hydrolyzed under acidic conditions (pH<7) into 1-naphthol as major product and traces of 2-naphthol. Based on these findings and literature data, we propose naphthalene 1,2-oxide as the primary product of AaP-catalyzed oxygenation of naphthalene. Using (18)O-labeled hydrogen peroxide, the origin of the oxygen atom transferred to naphthalene was proved to be the peroxide that acts both as oxidant (primary electron acceptor) and oxygen source.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Exposure to polycyclic aromatic hydrocarbons (PAH) and DNA damage were analyzed in coke oven (n = 37), refractory (n = 96), graphite electrode (n = 26), and converter workers (n = 12), whereas construction workers (n = 48) served as referents. PAH exposure was assessed by personal air sampling during shift and biological monitoring in urine post shift (1-hydroxypyrene, 1-OHP and 1-, 2 + 9-, 3-, 4-hydroxyphenanthrenes, SigmaOHPHE). DNA damage was measured by 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and DNA strand breaks in blood post shift. Median 1-OHP and SigmaOHPHE were highest in converter workers (13.5 and 37.2 microg/g crea). The industrial setting contributed to the metabolite concentrations rather than the air-borne concentration alone. Other routes of uptake, probably dermal, influenced associations between air-borne concentrations and levels of PAH metabolites in urine making biomonitoring results preferred parameters to assess exposure to PAH. DNA damage in terms of 8-oxo-dGuo and DNA strand breaks was higher in exposed workers compared to referents ranking highest for graphite-electrode production. The type of industry contributed to genotoxic DNA damage and DNA damage was not unequivocally associated to PAH on the individual level most likely due to potential contributions of co-exposures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVES: The aim of the study was to investigate the influence of continued injecting drug use, enrolment in an opiate substitution treatment programme (OSTP), or cessation of injecting drug use on the uptake and course of antiretroviral therapy (ART). Design A prospective observational study of all participants in the Swiss HIV Cohort Study followed between 1997 and 2006 was carried out. METHODS: We distinguished four groups of former or current injecting drug users (IDUs): (i) abstinent former IDUs; (ii) persons in OSTPs without concomitant injecting drug use; (iii) persons in OSTPs with concomitant injecting drug use; (vi) current IDUs. These groups were compared with a group of patients who had never been IDUs. Factors related to ART uptake and virological endpoints were analysed using logistic generalized estimating equations. RESULTS: We followed 8660 participants for 48 477 person-years; 29.7% were in the IDU HIV transmission group. The likelihood of being on ART at biannual visits was lower among individuals in OSTPs with concomitant injecting drug use [odds ratio (OR) 0.79; 95% confidence interval (CI) 0.71-0.89] and current IDUs (OR 0.80; 95% CI 0.67-0.96), compared with those who had never been IDUs (reference), abstinent former IDUs (OR 1.13; 95% CI 1.02-1.25) and individuals in OSTPs without injecting drug use (OR 1.18; 95% CI 1.06-1.31). The likelihood of suppressed viral replication on ART was similar among those who had never been IDUs, abstinent former IDUs and individuals in an OSTP without injecting drug use, and lower among those in OSTPs with concomitant drug use (OR 0.82; 95% CI 0.72-0.93) and current IDUs (OR 0.81; 0.65-1.00). Adherence to ART was decreased among persons with continued injecting drug use, and correlated with virological outcome. CONCLUSIONS: Uptake of and virological response to ART were improved among abstinent former IDUs and persons in OSTPs without concomitant injecting drug use, compared with persons with continued injecting drug use.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Acetylation and formylation of 3-phenyl-cycl[3.2.2]azine derivatives, in the presence of Lewis acids, have been Investigated. It has been found that the orientation of substitution in 2-carbomethoxy- 3-phenyl-cycl[3.2.2]azine for these two reactions, under Identical conditions, is different.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of bowel segments as bladder substitutes may result in chronic, impaired vitamin D and calcium metabolism, and ultimately in bone demineralization.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thirty-two multiparous Holstein cows were used to investigate the effects of chromium-l-methionine (Cr-Met) supplementation and dietary grain source on performance and lactation during the periparturient period. Cows were fed a total mixed ration consisting of either a barley-based diet (BBD) or a corn-based diet (CBD) from 21 d before anticipated calving through 28 d after calving. The Cr-Met was supplemented at dosages of 0 or 0.08 mg of Cr/kg of metabolic body weight. The study was designed as a randomized complete block design with 2 (Cr-Met levels) x 2 (grain sources) factorial arrangement. There was no Cr effect on prepartum dry matter intake (DMI) or postpartum DMI, body weight (BW), net energy balance, and whole tract apparent digestibility of nutrients. Prepartum DMI as a percentage of BW tended to increase with Cr-Met. Supplemental Cr-Met tended to increase milk yield whereas milk protein percentage decreased. Pre- and postpartum DMI, BW, net energy balance, milk yield, and milk composition were not affected by substituting ground barley with ground corn. The addition of Cr-Met increased prepartum DMI and tended to increase postpartum DMI of the BBD but not the CBD. The change in prepartum DMI was smaller when the BBD was supplemented with Cr-Met but remained unchanged when the CBD was supplemented with Cr-Met. Yields of crude protein and total solids in milk and prepartum digestibility of DM and organic matter tended to increase when Cr-Met was added to the BBD but remained unchanged when added to the CBD. Periparturient cows failed to respond to the grain source of the diet, whereas they showed greater response in milk yield to diets supplemented with Cr-Met. In conclusion, the present results demonstrate that the beneficial effect of Cr-Met supplementation during the periparturient period to improve feed intake may depend on the grain source of the diet.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE To evaluate the etiology and treatment of bilateral hydronephrosis not responding to bladder substitute drainage after ileal bladder substitution using an afferent isoperistaltic tubular segment. MATERIALS AND METHODS A retrospective analysis was performed of a consecutive series of 739 patients who had undergone bladder substitution from April 1985 to August 2012. RESULTS Of the 739 ileal bladder substitute patients, 10 (1.4%) developed bilateral hydronephrosis unresponsive to complete bladder substitute drainage. The etiology was stenosis of the afferent isoperistaltic tubular segment. The median interval to presentation was 131 months (range 45-192). The incidence of afferent tubular segment stenosis was significantly higher in the 61 ileal bladder substitute patients with recurrent urinary tract infection (9 [15%]) than in the 678 without recurrent urinary tract infection (1 [0.15%]; P <.001). Urine cultures revealed mixed infections (34%), Escherichia coli (18%), Staphylococcus aureus (13%), enterococci (11%), Candida (8%), Klebsiella (8%), and others (8%). Seven patients underwent 10 endourologic interventions, only 1 of which was successful (10%). After failed endourologic treatment, 7 open surgical revisions with resection of the stricture were performed, with all 7 (100%) successful. CONCLUSION Bilateral dilation of the upper urinary tract after ileal orthotopic bladder substitution unresponsive to complete bladder substitute drainage is likely to be caused by stenosis of the afferent isoperistaltic tubular segment. The stenosis occurs almost exclusively in patients with long-lasting, recurrent urinary tract infection and can develop many years after the ileal bladder substitution. Minimally invasive endourologic treatment is usually unsuccessful; however, open surgical revision offers excellent results.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper develops a process model of how and why complementarity and substitution form over time between contractual and relational governance in the context of information systems outsourcing. Our analysis identifies four distinct process patterns that explain this formation as the outcome of interaction processes between key elements of both contractual and relational governance. These patterns unveil the dynamic nature of complementarity and substitution. In particular, we show that the relationship between contractual and relational governance oscillates between complementarity and substitution. Those oscillations are triggered mainly by three types of contextual events (goal fuzziness, goal conflict, and goal misalignment). Surprisingly, substitution of informal control did not occur as an immediate reaction to external events but emerged as a consequence of preceding complementarity. Thus, our study challenges the prevailing view of an either/or dichotomy of complementarity and substitution by showing that they are causally connected over time.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As pituitary function depends on the integrity of the hypothalamic-pituitary axis, any defect in the development and organogenesis of this gland may account for a form of combined pituitary hormone deficiency (CPHD). A mutation in a novel, tissue-specific, paired-like homeodomain transcription factor, termed Prophet of Pit-1 (PROP1), has been identified as causing the Ames dwarf (df) mouse phenotype, and thereafter, different PROP1 gene alterations have been found in humans with CPHD. We report on the follow-up of two consanguineous families (n = 12), with five subjects affected with CPHD (three males and two females) caused by the same nucleotide C to T transition, resulting in the substitution of Arg-->Cys in PROP1 at codon 120. Importantly, there is a variability of phenotype, even among patients with the same mutation. The age at diagnosis was dependent on the severity of symptoms, ranging from 9 months to 8 yr. Although in one patient TSH deficiency was the first symptom of the disorder, all patients became symptomatic by exhibiting severe growth retardation and failure to thrive, which was mainly caused by GH deficiency (n = 4). The secretion of the pituitary-derived hormones (GH, PRL, TSH, LH, and FSH) declined gradually with age, following a different pattern in each individual; therefore, the deficiencies developed over a variable period of time. All of the subjects entered puberty spontaneously, and the two females also experienced menarche and periods before a replacement therapy was necessary.