Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Ann Oncol ; 34(2): 200-211, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36423745

RESUMO

BACKGROUND: Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)]. PATIENTS AND METHODS: c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961). RESULTS: Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance. CONCLUSIONS: c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.


Assuntos
Antineoplásicos Imunológicos , DNA Tumoral Circulante , Neoplasia Residual , Neoplasias de Mama Triplo Negativas , Humanos , Biomarcadores Tumorais/sangue , Mutação , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Estudos Prospectivos , Neoplasias de Mama Triplo Negativas/sangue , Neoplasias de Mama Triplo Negativas/diagnóstico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasia Residual/sangue , Neoplasia Residual/diagnóstico , Neoplasia Residual/tratamento farmacológico , Neoplasia Residual/genética , Antineoplásicos Imunológicos/uso terapêutico , DNA Tumoral Circulante/sangue
2.
ESMO Open ; 9(9): 103687, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39216186

RESUMO

BACKGROUND: In early breast cancer (EBC) patients, we aimed to determine whether circulating tumor DNA (ctDNA) analysis following primary surgery, before systemic therapy, identified molecular residual disease and was associated with risk of relapse and relapse-free survival (RFS). METHODS: Plasma was collected, retrospectively, before surgery, 1-14 weeks post-operatively, and before adjuvant therapy, and in a subset of patients after adjuvant therapy. A personalized, tumor-informed, multiplex PCR next generation sequencing assay (Signatera™) was used for ctDNA detection and quantification. The primary objective was to compare RFS and distant recurrence-free survival (DRFS) in patients with detected versus non-detected ctDNA. RESULTS: A total of 48 patients with EBC (median age 50.5 years) [34 hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-), 5 HER2+, 9 triple-negative breast cancer) were included. ctDNA was detected in 64.5% (20/31) of patients before surgery, and 35.4% (17/48) after surgery. ctDNA detection before surgery was associated with tumor grade (P = 0.019), ctDNA detection after surgery was associated with receptor subtype (P = 0.01). Patients with ctDNA detected after surgery had worse DRFS [hazard ratio = 5.5, 95% confidence interval (CI) 1.1-28.5, P = 0.04]. RFS in patients with ctDNA detected after surgery was worse than in those with lack of ctDNA detection, although not statistically significant (hazard ratio = 3.7, 95% CI 0.9-15.7, P = 0.073). Patients with ctDNA detected preoperatively or post-operatively had a trend towards worse RFS (hazard ratio = 7.8, 95% CI 0.9-63.7, P = 0.05) and DRFS (hazard ratio = 6.8, 95% CI 0.8-57, P = 0.07) compared with those with ctDNA undetected at both timepoints. ctDNA detection anticipated clinical relapse with a median lead time of 16 months. CONCLUSIONS: In patients with treatment-naive EBC, ctDNA is detectable after surgery. The absence of ctDNA at a single post-surgical timepoint is associated with improved DRFS, supporting the development of future trials studying de-escalation of systemic therapy.

3.
J Appl Microbiol ; 114(3): 886-98, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23181509

RESUMO

AIMS: To isolate and characterize bacteriocins produced by predominant species of lactic acid bacteria from faeces of elderly subjects. METHODS AND RESULTS: Screening over 70,000 colonies, from faecal samples collected from 266 subjects, using the indicator organisms Lactobacillus bulgaricus LMG 6901 and Listeria innocua DPC 3572, identified 55 antimicrobial-producing bacteria. Genomic fingerprinting following ApaI digestion revealed 15 distinct strains. The antimicrobial activities associated with 13 of the 15 strains were sensitive to protease treatment. The predominant antimicrobial-producing species were identified as Lactobacillus salivarius, Lactobacillus gasseri, Lactobacillus acidophilus, Lactobacillus crispatus and Enterococcus spp. A number of previously characterized bacteriocins, including ABP-118 and salivaricin B (from Lact. salivarius), enterocin B (Enterococcus faecium), lactacin B (Lact. acidophilus), gassericin T and a variant of gassericin A (Lact. gasseri), were identified. Interestingly, two antimicrobial-producing species, not generally associated with intestinally derived microorganisms were also isolated: Lactococcus lactis producing nisin Z and Streptococcus mutans producing mutacin II. CONCLUSION: These data suggest that bacteriocin production by intestinal isolates against our chosen targets under the screening conditions used was not frequent (0.08%). SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented are important due to growing evidence indicating bacteriocin production as a potential probiotic trait by virtue of strain dominance and/or pathogen inhibition in the mammalian intestine.


Assuntos
Bacteriocinas/isolamento & purificação , Enterococcus/isolamento & purificação , Intestinos/microbiologia , Lactobacillus/isolamento & purificação , Microbiota , Idoso , Proteínas de Bactérias/isolamento & purificação , Bacteriocinas/biossíntese , Impressões Digitais de DNA , DNA Bacteriano/genética , Enterococcus/genética , Enterococcus/metabolismo , Fezes/microbiologia , Humanos , Irlanda , Lactobacillus/genética , Lactobacillus/metabolismo , Probióticos , RNA Ribossômico 16S/genética
4.
J Appl Microbiol ; 111(2): 467-73, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21718396

RESUMO

AIMS: The aim of this investigation was to establish the degree of correlation between measurements from culture-dependent microbiological techniques and from next generation sequencing technologies. METHODS AND RESULTS: Data generated by both techniques were collected from faecal samples from 185 elderly Irish people involved in the ongoing ELDERMET study (http://eldermet.ucc.ie). The results for three groups of intestinal bacteria were compared. Bifidobacterium sp., Lactobacillus sp. and Enterobacteriaceae were enumerated on selective media through culture-dependent techniques, whereas proportions of these bacteria were determined through sequencing technology against the background of other bacteria. The Spearman's rank correlation coefficient determined a good correlation between results from culture-dependent microbiology and culture-independent techniques for all three bacterial groups assessed (correlation coefficients for Bifidobacterium sp., Lactobacillus sp. and Enterobacteriaceae were 0·380, 0·366 and 0·437, respectively). CONCLUSION: Correlation between the two methods implies that a single method is capable of profiling intestinal Bifidobacterium, Lactobacillus and Enterobacteriaceae populations. However, both methods have advantages that justify their use in tandem. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first extensive study to compare bacterial counts from culture-dependent microbiological techniques and from next generation sequencing technologies.


Assuntos
Bifidobacterium/isolamento & purificação , Enterobacteriaceae/isolamento & purificação , Fezes/microbiologia , Intestinos/microbiologia , Lactobacillus/isolamento & purificação , Adulto , Idoso , Bifidobacterium/genética , Contagem de Colônia Microbiana , Biologia Computacional , Meios de Cultura , DNA Bacteriano/genética , Enterobacteriaceae/genética , Genes de RNAr , Humanos , Lactobacillus/genética , Análise de Sequência de DNA
5.
Br J Anaesth ; 117(4): 536, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28077550
6.
J Dairy Sci ; 90(6): 2919-27, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17517732

RESUMO

The objective of this study was to assess the effect of dietary supplementation of cows on pasture with sunflower oil for conjugated linoleic acid (cis-9, trans-11 CLA) enrichment of milk, for the production of CLA-enriched cheese. A group of 40 autumn-calving dairy cows were assigned to either a control group (indoor feeding on grass silage ad libitum and 6 kg/d of a typical indoor concentrate) or an experimental group (on pasture, being fed 6 kg of a supplement containing 100 g/kg of sunflower oil per d). These diets were fed for 16 d, during which time milk was collected for pilot-scale hard cheese manufacture. The pasture-based diet with sunflower oil resulted in a significant effect on the milk fatty acid CLA content. The concentration of cis-9, trans-11 CLA in the milk produced from cows on this diet increased to 2.22 g/100 g of fatty acid methyl esters (FAME) after 14 d, compared with 0.46 g/100 g of FAME in milk produced on the control indoor diet. The content of cis-9, trans-11 CLA in the cheese manufactured from the indoor control milk was 0.78 g/100 g of FAME and that from the pasture-based sunflower oil milk was 1.93 g/100 g of FAME. The cheese was assessed during the ripening period and CLA concentrations were stable throughout the 6 mo of ripening. Other cheese variables (microbiology, composition, flavor, free AA) were monitored during the ripening period, and the cheese with the elevated CLA concentrations compared favorably with the control cheese. Thus, a pasture-based diet supplemented with an oil source rich in linoleic acid resulted in an enhanced CLA content of bovine milk fat, compared with an indoor grass silage-based diet.


Assuntos
Queijo/análise , Gorduras Insaturadas na Dieta/administração & dosagem , Ácidos Linoleicos Conjugados/administração & dosagem , Ácidos Linoleicos Conjugados/análise , Leite/química , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bovinos , Gorduras Insaturadas na Dieta/metabolismo , Suplementos Nutricionais , Feminino , Fermentação , Alimentos Orgânicos , Ácidos Linoleicos Conjugados/metabolismo , Óleos de Plantas/administração & dosagem , Óleos de Plantas/química , Óleos de Plantas/metabolismo , Distribuição Aleatória , Óleo de Girassol
7.
Environ Health Perspect ; 70: 105-11, 1986 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3830097

RESUMO

Certain short-chain carboxylic acids (SCCA) appear to share a common teratogenic potential, although the structural requirements for activity remain obscure. By using a whole rat embryo culture model system, several biochemical processes have been examined, either as potential initial sites of teratogenic action or as early steps in the pathway to malformation. Valproate, methoxyacetate, and butyrate were the prototype SCCA examined. Measurement of [14C]glucose utilization and lactate production confirmed that energy production by the early organogenesis embryo is predominantly from glycolysis. While the positive control agent, iodoacetate, caused a significant inhibition of lactate production, none of the SCCA affected this process or glucose utilization at teratogenic concentrations. Valproate did not influence embryonic acetyl CoA levels, in marked contrast to the reported response of adult liver, the other major target of valproate toxicity. Pinocytosis by the visceral yolk sac (VYS) was measured by the uptake of [125I]polyvinylpyrrolidone. This process ultimately supplies the embryo with amino-acids and is essential for normal development. SCCA induce morphological abnormalities of the VYS in embryo culture. Pinocytosis was slightly reduced by valporate, but not the other SCCA. However, comparison with the action of an antiserum, for which inhibition of pinocytosis is the initial teratogenic insult, suggests that this is not the mechanism for valproate. Incorporation of [3H]thymidine into embryo or yolk sac was not affected after 3 hr of SCCA exposure, but there was a marked effect of the positive control, hydroxyurea. This suggests that DNA synthesis is not directly influenced by SCCA.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Ácidos Carboxílicos/toxicidade , Embrião de Mamíferos/efeitos dos fármacos , Teratogênicos , Acetilcoenzima A/metabolismo , Animais , Replicação do DNA/efeitos dos fármacos , Embrião de Mamíferos/fisiologia , Glicólise/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Pinocitose/efeitos dos fármacos , Ratos , Relação Estrutura-Atividade
8.
Child Abuse Negl ; 17(4): 515-26, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8402254

RESUMO

Recent recognition of child-to-child and adolescent-to-child sexual abuse raises the question, for the courts, educators, clinicians, and lay individuals, where do we draw the line between normal childhood sexual play, and abuse. This paper presents the results of a survey on normative childhood sexual play and games experiences that was distributed to 300 undergraduates at an all women's college. One hundred-twenty-eight returned the survey, 85% of whom described a childhood sexual game experience. Of these women, 44% described cross-gender play and there was a trend for women who had described cross-gender experiences to have seen the play as involving persuasion, manipulation, or coercion. A strong relationship was found between abuse and cross-gender play. Level of physical involvement in the game was correlated with perceptions of normality. A typology of six kinds of sexual play experiences was derived. Results are discussed in terms of their relation to differentiating childhood sexual abuse from play and gender socialization influences relating to the role rehearsal of coercive or manipulative relationships.


Assuntos
Abuso Sexual na Infância/diagnóstico , Jogos e Brinquedos , Comportamento Sexual/classificação , Adolescente , Comportamento do Adolescente , Adulto , Criança , Abuso Sexual na Infância/psicologia , Comportamento Infantil , Pré-Escolar , Diagnóstico Diferencial , Feminino , Identidade de Gênero , Humanos , Fatores Sexuais , Comportamento Sexual/psicologia , Relações entre Irmãos , Inquéritos e Questionários
9.
Am J Vet Res ; 60(11): 1441-4, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10566824

RESUMO

OBJECTIVE: To compare serum disposition of flunixin meglumine after i.v. administration of a bolus to horses, donkeys, and mules. ANIMALS: 3 clinically normal horses, 5 clinically normal donkeys, and 5 clinically normal mules. PROCEDURE: Blood samples were collected at time zero (before) and 5, 10, 15, 30, and 45 minutes, and at 1, 1.25, 1.5, 1.75, 2, 2.5, 2.75, 3, 3.5, 4, 4.5, 5, 5.5, 6, and 8 hours after i.v. administration of a bolus of flunixin meglumine (1.1 mg/kg of body weight). Serum was analyzed in duplicate by the use of high-performance liquid chromatography for determination of flunixin meglumine concentrations. The serum concentration-time curve for each horse, donkey, and mule were analyzed separately to estimate noncompartmental pharmacokinetic variables RESULTS: Mean (+/-SD) area under the curve for donkeys (646 +/- 148 minute x microg/ml) was significantly less than for horses (976 +/- 168 minute x microg/ml) or for mules (860 +/- 343 minute x microg/ml). Mean residence time for donkeys (54.6 +/- 7 minutes) was significantly less than for horses (110 +/- 24 minutes) or for mules (93 +/- 30 minutes). Mean total body clearance for donkeys (1.78 +/- 0.5 ml/kg/h) was significantly different from that for horses (1.14 +/- 0.18 ml/kg/h) but not from that for mules (1.4 +/- 0.5 ml/kg/h). Significant differences were not found between horses and mules for any pharmacokinetic variable. CONCLUSION AND CLINICAL RELEVANCE: Significant differences exist with regard to serum disposition of flunixin meglumine in donkeys, compared with that for horses and mules. Consequently, flunixin meglumine dosing regimens used in horses may be inappropriate for use in donkeys.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Clonixina/análogos & derivados , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/sangue , Área Sob a Curva , Clonixina/administração & dosagem , Clonixina/sangue , Clonixina/farmacocinética , Equidae , Feminino , Cavalos , Injeções Intravenosas , Masculino , Taxa de Depuração Metabólica , Especificidade da Espécie , Fatores de Tempo
10.
Int J Obstet Anesth ; 11(1): 57-60, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15321578

RESUMO

We present a case in which a 27-year-old primigravida was found to have an intracranial tumour during the first stage of labour. We review previous reports of similar cases and discuss the management options.

11.
J Thromb Haemost ; 9(2): 282-92, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21091865

RESUMO

BACKGROUND: Bleeding after cardiopulmonary bypass (CPB) is a major cause of morbidity and mortality and consumes large amounts of blood. Identifying patients at increased risk of bleeding secondary to hemostatic impairment may improve clinical outcomes by allowing early intervention. METHODS: This present study recruited 77 patients undergoing CPB and measured coagulation screens, coagulation factors, TEG(®), Rotem(®) and thrombin generation (TG) before surgery and 30 min after heparin reversal. The tests were analyzed to investigate whether they identified patients at increased risk of excess bleeding (defined as > 1000 mL) in the first 24 h postoperatively. RESULTS: Patients who bled > 1000 mL had a lower: platelet count (P < 0.02), factors (F)IX, X and XI (P < 0.005), endogenous thrombin potential (ETP) and an initial rate of TG (P < 0.02) and higher activated partial thromboplastin time (aPTT) (P < 0.001) than patients who bled < 1000 mL. Receiver operating characteristic (ROC) analysis was significant for post-operative TG and aPTT (P < 0.001). Furthermore, reduced pre-operative TG was associated with increased postoperative bleeding (P < 0.02). Pre- and postoperative TG were correlated (ρ = 0.7, P < 0.001). TEG(®), Rotem(®) and prothrombin time (PT) at either time point were not associated with increased bleeding. CONCLUSION: These data suggest that pre-operative defects in the propagation phase of hemostasis are exacerbated during CPB, contributing to bleeding post-CPB. TG taken both pre- and postoperatively could potentially be used to identify patients at an increased risk of bleeding post-CPB.


Assuntos
Ponte de Artéria Coronária , Hemorragia Pós-Operatória , Trombina/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Testes de Coagulação Sanguínea , Calibragem , Hemostasia , Humanos , Pessoa de Meia-Idade , Curva ROC
15.
Anaesthesia ; 60(12): 1173-8, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16288614

RESUMO

Continuing aspirin up until surgery in cardiac surgical patients may increase peri-operative blood loss. It is possible that there is a subset of patients particularly sensitive to aspirin. The platelet function analyser (PFA-100) can demonstrate the antiplatelet effect of aspirin. This study was designed to assess the effect of daily 75 mg aspirin on platelet function, as measured by the PFA-100, in 92 patients with ischaemic heart disease. Patients were classified into three groups according to their PFA-100 results; aspirin hyper-responders (16%), aspirin normal responders (33%) and aspirin non-responders (51%). The PFA-100 has potential as a screening tool to identify patients who are either hyper-responsive or resistant to aspirin. Pre-operative PFA-100 screening to isolate aspirin hyper-responders could enable the vast majority of patients to continue with aspirin therapy pre-operatively, avoiding the risks of stopping treatment.


Assuntos
Aspirina/farmacologia , Plaquetas/efeitos dos fármacos , Isquemia Miocárdica/sangue , Inibidores da Agregação Plaquetária/farmacologia , Adulto , Idoso , Plaquetas/fisiologia , Resistência a Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Agregação Plaquetária/efeitos dos fármacos , Testes de Função Plaquetária/métodos , Cuidados Pré-Operatórios/métodos
16.
Appl Environ Microbiol ; 63(4): 1434-40, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9097441

RESUMO

The conjugative 63-kb lactococcal plasmid pMRC01 encodes bacteriophage resistance and production of and immunity to a novel broad-spectrum bacteriocin, designated lacticin 3147 (M.P. Ryan, M.C. Rea, C. Hill, and R.P. Ross, Appl. Environ. Microbiol. 62:612-619, 1996). The phage resistance is an abortive infection mechanism which targets the phage-lytic cycle at a point after phage DNA replication. By using the genetic determinants for bacteriocin immunity encoded on the plasmid as a selectable marker, pMRC01 was transferred into a variety of lactococcal starter cultures to improve their phage resistance properties. Selection of resulting transconjugants was performed directly on solid media containing the bacteriocin. Since the starters exhibited no spontaneous resistance to the bacteriocin as a selective agent, this allowed the assessment of the transfer of the naturally occurring plasmid into a range of dairy starter cultures. Results demonstrate that efficient transfer of the plasmid was dependent on the particular recipient strain chosen, and while high-frequency transfer (10(-3) per donor) of the entire plasmid to some strains was observed, the plasmid could not be conjugated into a number of starters. In this study, transconjugants for a number of lactococcal starter cultures which are phage resistant and bacteriocin producing have been generated. This bacteriocin-producing phenotype allows for control of nonstarter flora in food fermentations, and the phage resistance property protects the starter cultures in industry. The 63-kb plasmid was also successfully transferred into Lactococcus lactis MG1614 cells via electroporation.


Assuntos
Bacteriocinas/genética , Bacteriófagos , Laticínios/microbiologia , Microbiologia de Alimentos , Lactococcus lactis/virologia , Plasmídeos/genética , Bacteriocinas/metabolismo , Plasmídeos/metabolismo
17.
Appl Opt ; 35(33): 6479-93, 1996 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-21127672

RESUMO

The technique of Fabry-Perot CCD annular-summing spectroscopy, with particular emphasis on applications in aeronomy, is discussed. Parameter choices for optimizing performance by the use of a standard format CCD array are detailed. Spectral calibration methods, techniques for determining the ring pattern center, and effects imposed by limited radial resolution caused by superpixel size, variable by on-chip binning, are demonstrated. The technique is carefully evaluated experimentally relative to the conventional scanning Fabry-Perot that uses a photomultiplier detector. We evaluate three extreme examples typical of aeronomical spectroscopy using calculated signal-to-noise ratios. Predicted sensitivity gains of 10-30 are typical. Of the cases considered, the largest savings in integration time are estimated for the day sky thermospheric O(1)D case, in which the bright sky background dominates the CCD read noise. For profile measurements of faint night sky emission lines, such as exospheric hydrogen Balmer-α, long integration times are required to achieve useful signal-to-noise ratios. In such cases, CCD read noise is largely overcome. Predictions of a factor of 10-15 savings in integration time for night sky Balmer-α observations are supported by field tests. Bright, isolated night sky lines such as thermospheric O(1)D require shorter integration times, and more modest gains dependent on signal level are predicted. For such cases it appears from estimate results that the Fabry-Perot CCD annular-summing technique with a conventional rectangular format may be outperformed by a factor of 2-5 by special CCD formats or by unusual optical coupling configurations that reduce the importance of read noise, based on the ideal transmission for any additional optics used in these configurations.

18.
J Appl Microbiol ; 94(1): 138-45, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12492934

RESUMO

AIMS: To assess strains of Lactobacillus, Lactococcus, Pediococcus and Bifidobacterium for their ability to produce the health-promoting fatty acid conjugated linoleic acid (CLA) from free linoleic acid. METHODS AND RESULTS: In this study, strains of Lactobacillus, Lactococcus, Pediococcus and Bifidobacterium were grown in medium containing free linoleic acid. Growth of the bacteria in linoleic acid and conversion of the linoleic acid to CLA was assessed. Of the bacteria assessed, nine strains of Bifidobacterium produced the c9, t11 CLA isomer from free linoleic acid. The t9, t11 CLA isomer was also produced by some strains, but at much lower concentrations. CONCLUSIONS: The production of CLA by bifidobacteria exhibited considerable interspecies variation. Bifidobacterium breve and B. dentium were the most efficient CLA producers among the range of strains tested, with B. breve converting up to 65% linoleic acid to c9, t11 CLA when grown in 0.55 mg ml(-1) linoleic acid. Strains also varied considerably with respect to their sensitivity to linoleic acid. SIGNIFICANCE AND IMPACT OF THE STUDY: The production of CLA by probiotic bifidobacteria offers a possible mechanism for some health-enhancing properties of bifidobacteria and provides novel opportunities for the development of functional foods.


Assuntos
Bifidobacterium/metabolismo , Ácido Linoleico/biossíntese , Adulto , Cromatografia Gasosa , Meios de Cultura , Ácidos Graxos/análise , Fezes/microbiologia , Humanos , Lactente , Intestinos/microbiologia , Isomerismo , Lactobacillus/metabolismo , Lactococcus/metabolismo , Pediococcus/metabolismo , Probióticos/metabolismo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa