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2.
Artigo em Inglês | MEDLINE | ID: mdl-31403133

RESUMO

OBJECTIVE: To compare complication rates following amniocentesis in twin gestations, according to sampling technique and number of needle insertions. STUDY DESIGN: A retrospective cohort study of all women with twin gestations who underwent amniocentesis and delivered in a single university affiliated medical center during 2002-2016. Amniocentesis was performed either through one uterine entry with passage through the inter-twin membrane or through two different entries to the two amniotic sacs. Pregnancy outcome of women that underwent single needle insertion amniocentesis, was compared to this of double needle insertion. Primary outcome was neonatal complications within 4 weeks after amniocentesis (late abortion, chorioamnionitis, preterm premature rupture of membranes, or hospitalization due to related symptoms). Secondary outcomes were gestational week at delivery and labor characteristics. RESULTS: The study group comprised 212 women. Of them, 73 (34.4%) underwent a single uterine insertion and 139 (65.6%) two separate needle insertions. Baseline characteristics did not differ between the groups. The amniocentesis complication rate was 13.7% in the single insertion group and 16.5% in the double insertion group (p = 0.587). Multivariate analysis found that a single insertion method had no statistically significant influence on complication rate, after making adjustments for potential confounders (OR = 1.085, 95% CI 0.4-2.9; p = 0.871). Other labor characteristics were similar between the groups. CONCLUSION: Needle insertion technique in twin gestation amniocentesis was not associated with procedure related complications.

3.
Ultrasound Obstet Gynecol ; 54(2): 262-269, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30426587

RESUMO

OBJECTIVE: To assess the learning curves of trainees during a structured offline/hands-on training program for the ultrasonographic diagnosis of deep infiltrating endometriosis (DIE). METHODS: Four trainees (all Ob/Gyn postgraduates with at least 5 years' experience in ultrasonography in obstetrics and gynecology, but with no experience of sonographic examination of DIE) participated in the study. They underwent a 2-week training program with a single trainer. Day 1 was devoted to theoretical issues and guided offline analysis of 10 three-dimensional ultrasound volumes. During the following days, four sessions of real-time sonographic examinations were performed in a DIE referral center ultrasound unit. In between these sessions, the trainees analyzed four datasets offline, each containing 25 volumes. At the end of each set, misinterpreted volumes were reassessed with the trainer. Presence or absence of DIE at surgery was considered the gold standard. The trainees' learning process was evaluated by learning-curve cumulative summation (LC-CUSUM) and the deviations of the trainees' level of performance at the control stage was assessed by CUSUM (standard CUSUM), for different locations of DIE. RESULTS: The trainees reached competence after an average of 17 (range, 14-21) evaluations for bladder, 40 (range, 30-60) for rectosigmoid, 25 (range, 14-34) for forniceal, 44 (range, 25-66) for uterosacral ligament (USL) and 21 (range, 14-43) for rectovaginal septum (RVS) locations of DIE, and then kept the process under control, with error levels of less than 4.5% until the end of the test. The overall accuracy for each trainee in diagnosis of DIE at the different locations ranged from 0.91 to 0.98 for bladder DIE, from 0.80 to 0.94 for rectosigmoid DIE, from 0.90 to 0.94 for forniceal DIE, from 0.79 to 0.82 for USL DIE and from 0.89 to 0.98 for RVS DIE. CONCLUSIONS: The suggested 2-week training program, based on a mixture of offline and live scanning sessions, is feasible and apparently provides effective training for the ultrasonographic diagnosis of DIE. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.


Assuntos
Endometriose/diagnóstico por imagem , Ginecologia/educação , Curva de Aprendizado , Ultrassonografia/métodos , Competência Clínica/estatística & dados numéricos , Educação/métodos , Educação/tendências , Endometriose/patologia , Endometriose/cirurgia , Feminino , Humanos , Itália/epidemiologia , Ligamentos/diagnóstico por imagem , Ligamentos/patologia , Reto/diagnóstico por imagem , Reto/patologia , Sensibilidade e Especificidade , Doenças da Bexiga Urinária/diagnóstico por imagem , Anormalidades Urogenitais/diagnóstico por imagem , Anormalidades Urogenitais/patologia , Útero/anormalidades , Útero/diagnóstico por imagem , Útero/patologia , Vagina/diagnóstico por imagem , Vagina/patologia
4.
S Afr Med J ; 107(11): 952-953, 2017 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-29262935

RESUMO

There is little published information on effective treatment of Kaposi's sarcoma (KS) in children in low-income countries. We prospectively treated 12 patients with an institutional review board-approved protocol consisting of four monthly courses of doxorubicin (Adriamycin), bleomycin and vincristine sulphate (ABV), with highly active antiretroviral therapy (HAART) plus co-trimoxazole prophylaxis for those who were HIV-positive, with additional vincristine if remission was not achieved after 4 months. Maintenance HAART plus co-trimoxazole was given to all HIV-positive patients. A fine-needle aspirate and CD4+ count were done if possible, and staging was performed according to Mitsuyasu. Eight of ten HIV-positive patients with stage III - IVB disease, and both HIV-negative patients with stage I disease, were in remission after 473 - 1 490 (mean 939) days. One patient died after absconding during treatment, and one died from neutropenia-related pulmonary infection. ABV with or without HAART is an effective treatment option for children with KS.


Assuntos
Infecções por HIV , Sarcoma de Kaposi , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Terapia Antirretroviral de Alta Atividade/métodos , Bleomicina/administração & dosagem , Bleomicina/efeitos adversos , Contagem de Linfócito CD4/métodos , Camarões , Criança , Pré-Escolar , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Feminino , Infecções por HIV/sangue , Infecções por HIV/complicações , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Estadiamento de Neoplasias , Sarcoma de Kaposi/complicações , Sarcoma de Kaposi/diagnóstico , Sarcoma de Kaposi/tratamento farmacológico , Sarcoma de Kaposi/mortalidade , Resultado do Tratamento , Vincristina/administração & dosagem , Vincristina/efeitos adversos
5.
S Afr Med J ; 106(7): 10693, 2016 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-27384372

RESUMO

Contradictory findings have been reported from Africa with regard to the risk of developing Burkitt's lymphoma (BL) in sickle cell trait (AS)carriers. Haemoglobin electrophoresis was performed in 78 BL patients in the Northwest region of Cameroon, and in 78 nearest-neighbourcontrols of the same age, sex and tribe from the same village. AS was confirmed in 4 of 78 (5.13%) BL patients and in 11 of 78 (14.10%)controls (χ2, p=0.052; Fisher's exact, one-tailed, p=0.050). Sickle cell trait carriers had a marginal statistically reduced risk of developing BL.

7.
Ultrasound Obstet Gynecol ; 47(2): 217-23, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25728404

RESUMO

OBJECTIVE: To determine the association between sonographic assessment of fetal biparietal diameter (BPD) and pregnancy outcome. METHODS: This was a retrospective cohort study of pregnancies at 37-42 weeks of gestation which had antepartum sonographic measurement of BPD within 7 days before delivery. Eligibility was limited to singleton pregnancies with neither known structural or chromosomal abnormalities nor prelabor Cesarean delivery (CD). The association of BPD with outcome was analyzed using multivariate logistic regression, receiver-operating characteristics curves and stratification according to BPD quartiles. RESULTS: In total, 3229 women were eligible for analysis, of whom 2483 (76.9%) had a spontaneous vaginal delivery (SVD), 418 (12.9%) underwent operative vaginal delivery (OVD) and 328 (10.2%) underwent CD. The mean BPD in the obstetric intervention groups (OVD and CD) was significantly higher than that in the SVD group (P < 0.001). After adjusting for confounders, increased BPD was an independent risk factor such that higher values of BPD were associated with progressively higher risk of obstetric intervention (adjusted odds ratio, 1.05 for each 1-mm increase in BPD (95% CI, 1.02-1.09)), but no clear cut-off value for obstetric intervention was found. The fourth quartile group (BPD ≥ 97 mm) was associated with a significantly lower SVD rate (P < 0.001) and higher OVD rate (P = 0.04), relative to the first (BPD 88-90 mm) and second (BPD 91-93 mm) quartile groups, with no apparent adverse impact on immediate neonatal outcome. CONCLUSIONS: Increased BPD within the week prior to delivery is an independent risk factor such that higher values of BPD are associated with progressively higher risk of obstetric intervention; however, in our experience, no adverse neonatal outcome resulted from such intervention. Thus, increased BPD should not discourage a trial of vaginal delivery.


Assuntos
Parto Obstétrico/estatística & dados numéricos , Desenvolvimento Fetal , Lobo Parietal/diagnóstico por imagem , Resultado da Gravidez , Ultrassonografia Pré-Natal/métodos , Adulto , Parto Obstétrico/métodos , Feminino , Humanos , Modelos Logísticos , Análise Multivariada , Complicações do Trabalho de Parto/etiologia , Tamanho do Órgão , Lobo Parietal/embriologia , Lobo Parietal/crescimento & desenvolvimento , Valor Preditivo dos Testes , Gravidez , Curva ROC , Estudos Retrospectivos , Fatores de Risco
8.
Ultrasound Obstet Gynecol ; 46(1): 73-81, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25251479

RESUMO

OBJECTIVE: To assess the accuracy and determine the optimal threshold of sonographic cervical length (CL) for the prediction of preterm delivery (PTD) in women with twin pregnancies presenting with threatened preterm labor (PTL). METHODS: This was a retrospective study of women with twin pregnancies who presented with threatened PTL and underwent sonographic measurement of CL in a tertiary center. The accuracy of CL in predicting PTD in women with twin pregnancies was compared with that in a control group of women with singleton pregnancies. RESULTS: Overall, 218 women with a twin pregnancy and 1077 women with a singleton pregnancy, who presented with PTL, were included in the study. The performance of CL as a predictive test for PTD was similar in twins and singletons, as reflected by the similar correlation between CL and the examination-to-delivery interval (r, 0.30 vs 0.29; P = 0.9), the similar association of CL with risk of PTD, and the similar areas under the receiver-operating characteristics curves for differing delivery outcomes (range, 0.653-0.724 vs 0.620-0.682, respectively; P = 0.3). The optimal threshold of CL for any given target sensitivity or specificity was lower in twin than in singleton pregnancies. However, in order to achieve a negative predictive value of 95%, a higher threshold (28-30 mm) should be used in twin pregnancies. Using this twin-specific CL threshold, women with twins who present with PTL are more likely to have a positive CL test, and therefore to require subsequent interventions, than are women with singleton pregnancies with PTL (55% vs 4.2%, respectively). CONCLUSION: In women with PTL, the performance of CL as a test for the prediction of PTD is similar in twin and singleton pregnancies. However, the optimal threshold of CL for the prediction of PTD appears to be higher in twin pregnancies, mainly owing to the higher baseline risk for PTD in these pregnancies.


Assuntos
Medida do Comprimento Cervical/métodos , Trabalho de Parto Prematuro/diagnóstico por imagem , Ultrassonografia Pré-Natal/métodos , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Gravidez , Gravidez de Gêmeos , Estudos Retrospectivos , Sensibilidade e Especificidade
9.
Heart Lung Vessel ; 6(4): 274-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25436209

RESUMO

INTRODUCTION: Our study primarily aimed at investigating the effect of isoproterenol infusion on tissue oxygen saturation in patients with septic shock. The secondary aim was to assess the relation between cardiac index, central venous oxygen saturation and tissue oxygen saturation. METHODS: This retrospective study was conducted from December 2010 to March 2012. We included 14 consecutive patients with septic shock treated with isoproterenol. All patients were monitored by cardiac index and tissue oxygen saturation. From medical charts, routine hemodynamic data were extracted one hour before and six hours after the onset of isoproterenol infusion. RESULTS: From baseline to H6, tissue oxygen saturation levels rise from 78 [72-82]% to 85 [78-88]% (p = 0.03). Isoproterenol infusion was associated with an increase of central venous oxygen saturation (from 67 [65-74]% to 84 [77-86]%, p = 0.02) and cardiac index (from 2.9 [2.7-3.1] L/min/m² to 3.9 [3.0-4.4] L/min/m², p = 0.006). Tissue oxygen saturation was correlated neither to cardiac index (p = 0.14, R(2) = 0.08) nor to central venous oxygen saturation (p = 0.19, R(2) = 0.10). CONCLUSIONS: Use of isoproterenol was associated with an increase of tissue oxygen saturation. This increase was not correlated to cardiac index, suggesting a decoupling between macrocirculation and microcirculation.

10.
Ultrasound Obstet Gynecol ; 44(6): 661-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24777952

RESUMO

OBJECTIVE: To determine whether sonographically measured cervical length is an effective predictive tool in women with threatened preterm labor and a history of past spontaneous preterm delivery. METHODS: This was a retrospective cohort study of all women with singleton pregnancies who presented with preterm labor at less than 34 + 0 weeks' gestation and underwent sonographic measurement of cervical length in a tertiary medical center between 2007 and 2012. The accuracy of cervical length in predicting preterm delivery was compared between women with and those without a history of spontaneous preterm delivery. Women with risk factors for preterm delivery other than a history of preterm delivery were excluded from both groups. RESULTS: Overall, 1023 women who presented with preterm labor met the study criteria, of whom 136 (13.3%) had a history of preterm delivery (past-PTD group) and 887 (86.7%) had no risk factors for preterm delivery (low-risk group). The rate of preterm delivery was significantly higher for women with a history of preterm delivery (36.8% vs 22.5%; P < 0.001). Cervical length was significantly correlated with the examination-to-delivery interval in low-risk women (r = 0.32, P < 0.001) but not in women who had had a previous preterm delivery (r = 0.07, P = 0.4). On multivariable analysis, cervical length was independently associated with the risk of preterm delivery for women in the low-risk group but not for women with a history of previous preterm delivery. For women with previous preterm delivery who presented with threatened preterm labor, cervical length failed to distinguish between those who did and those who did not deliver prematurely (area under the receiver-operating characteristics curve range, 0.475-0.506). When using standardized thresholds, the sensitivity and specificity of cervical length for the prediction of preterm delivery were significantly lower in women with previous preterm delivery than in women with no risk factors for preterm delivery. CONCLUSION: Cervical length appears to be of limited value in the prediction of preterm delivery among women with threatened preterm labor who are at high risk for preterm delivery owing to a history of spontaneous preterm delivery in a previous pregnancy.


Assuntos
Medida do Comprimento Cervical , Trabalho de Parto Prematuro/diagnóstico por imagem , Nascimento Prematuro/diagnóstico por imagem , Adulto , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Humanos , Modelos Logísticos , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Nascimento Prematuro/etiologia , Curva ROC , Estudos Retrospectivos , Fatores de Risco , Sensibilidade e Especificidade
11.
Int J Obstet Anesth ; 17(3): 243-6, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18499434

RESUMO

OBJECTIVE: To evaluate the attitude of expectant fathers to the use of epidural analgesia during labor and to compare it to the attitude of their partner. METHODS: The study group consisted of consecutive expectant, first-time parents who presented at the delivery room of a major medical center over a 3-month period. Only those with a single, term fetus in cephalic presentation were included. Both partners were asked to complete a questionnaire on desire to receive epidural analgesia firstly on admission and again later during labor at first discussion of the use of epidural analgesia with medical staff. Findings were compared between partners, between the two time points and with the actual use of epidural analgesia in labor. The effect of various socio-demographic variables on this decision was analyzed. RESULTS: One hundred fifty couples completed the study. On admission, 64.1% of the expectant fathers and 78.6% of the expectant mothers expressed a preference for epidural analgesia (P=0.01). Later in labor, the corresponding rates were 77.9% and 87.4%. In total 95.3% of the women received epidural analgesia. There was no effect of age, level of education, salary, or attendance in a birth preparatory course on the decision to use epidural analgesia by either partner. CONCLUSION: The decision to use epidural analgesia differs between partners, changes during the course of labor and is unrelated to socio-demographic factors.


Assuntos
Analgesia Epidural/psicologia , Atitude , Parto Obstétrico/psicologia , Pai/psicologia , Mães/psicologia , Adulto , Analgesia Epidural/estatística & dados numéricos , Pai/estatística & dados numéricos , Feminino , Humanos , Dor do Parto/psicologia , Masculino , Mães/estatística & dados numéricos , Medição da Dor , Gravidez , Fatores Socioeconômicos , Fatores de Tempo
12.
Ultrasound Obstet Gynecol ; 23(6): 594-8, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15170802

RESUMO

OBJECTIVE: To investigate whether uterine contractions at the time of a Cesarean section have an impact on future presence and location of a cervical Cesarean scar. METHODS: A targeted transvaginal ultrasound examination of the fetus, uterus and cervix was done in 2973 consecutive women at 14-16 weeks' gestation. The sonographer was blinded to the women's previous obstetric histories. The presence and location of a sonographic cervical hypoechogenic line, which probably represented a Cesarean scar, was recorded. RESULTS: There were 180 women with a previous Cesarean section performed before the start of uterine contractions and 173 with a Cesarean section performed during contractions in labor. The cervical hypoechogenic line was more common in sections performed during contractions (75.7% vs. 52.7%; P < 0.001) and was more distally located from the internal os (17.9 +/- 9.4 vs. 14.6 +/- 9.1 mm; P = 0.01). A hypoechogenic line was observed in 21/2620 women without a previous Cesarean section, representing a false-positive rate of 0.8%. CONCLUSION: Cesarean sections, especially those done during uterine contractions, are actually performed through cervical tissue. This finding is in agreement with the physiological process of cervical effacement during contractions.


Assuntos
Cesárea , Cicatriz/diagnóstico por imagem , Contração Uterina , Colo do Útero/diagnóstico por imagem , Recesariana , Cicatriz/etiologia , Feminino , Idade Gestacional , Humanos , Primeira Fase do Trabalho de Parto , Gravidez , Resultado da Gravidez , Estudos Prospectivos , Ultrassonografia Pré-Natal , Útero/diagnóstico por imagem , Nascimento Vaginal Após Cesárea
13.
Clin Nephrol ; 58(6): 411-6, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12508962

RESUMO

BACKGROUND AND AIM: Beta2-microglobulin (beta2-m) is a polypeptide, which is freely filtered through the glomerular basement membrane and absorbed almost entirely by the proximal tubular cells. Preeclampsia, a common complication of pregnancy, is characterized by pathological renal changes, mainly glomerular lesions. The aim of the present study was to investigate whether serum beta2-m measured in the early stages of pregnancy could be used as a marker to predict hypertensive complications in women at increased risk. PATIENTS AND METHODS: Serum beta2-m concentrations were prospectively measured in 75 pregnant women with history of chronic hypertension, chronic renal disease, chronic vascular disease or preeclampsia and compared with those in 16 healthy pregnant women. RESULTS: Of the 75 women in the study group, 10 (13%) developed preeclampsia and 20 (26%) had other complications, such as intrauterine growth restriction (n = 8), fetal or neonatal loss (n = 9) and delivery before 30 weeks of gestation (n = 8). Gestational age at delivery, birth weight and cesarean section rate were significantly worse in the patients with complications than in those without and in the healthy controls. No significant difference was detected in early serum beta2-m concentrations between the women who later developed preeclampsia or other complications and those who did not. There was a significant positive correlation of beta2-m concentrations with serum creatinine level (R2 = 0.394, p < 0.001), but not with gestational week at blood collection. CONCLUSION: Serum beta2-m concentrations are not predictive of the development of preeclampsia or other complications in woman at risk.


Assuntos
Pré-Eclâmpsia/epidemiologia , Complicações na Gravidez/epidemiologia , Microglobulina beta-2/sangue , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Testes de Função Renal , Pré-Eclâmpsia/diagnóstico , Valor Preditivo dos Testes , Gravidez , Complicações na Gravidez/diagnóstico , Estudos Prospectivos , Medição de Risco
14.
Environ Microbiol ; 1(6): 525-33, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11207774

RESUMO

Symbioses between the root nodule-forming, nitrogen-fixing actinomycete Frankia and its angiospermous host plants are important in the nitrogen economies of numerous terrestrial ecosystems. Molecular characterization of Frankia strains using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analyses of the 16S rRNA-ITS gene and of the nifD-nifK spacer was conducted directly on root nodules collected worldwide from Casuarina and Allocasuarina trees. In their native habitats in Australia, host species contained seven distinctive sets of Frankia in seven different molecular phylogenetic groups. Where Casuarina and Allocasuarina trees are newly planted outside Australia, they do not normally nodulate unless Frankia is introduced with the host seedling. Nodules from Casuarina trees introduced outside Australia over the last two centuries were found to contain Frankia from only one of the seven phylogenetic groups associated with the host genus Casuarina in Australia. The phylogenetic group of Frankia found in Casuarina and Allocasuarina trees introduced outside Australia is the only group that has yielded isolates in pure culture, suggesting a greater ability to survive independently of a host. Furthermore, the Frankia species in this group are able to nodulate a wider range of host species than those in the other six groups. In baiting studies, Casuarina spp. are compatible with more Frankia microsymbiont groups than Allocasuarina host spp. adapted to drier soil conditions, and C. equisetifolia has broader microsymbiont compatibility than other Casuarina spp. Some Frankia associated with the nodular rhizosphere and rhizoplan, but not with the nodular tissue, of Australian hosts were able to nodulate cosmopolitan Myrica plants that have broad microsymbiont compatibility and, hence, are a potential host of Casuarinaceae-infective Frankia outside the hosts' native range. The results are consistent with the idea that Frankia symbiotic promiscuity and ease of isolation on organic substrates, suggesting saprophytic potential, are associated with increased microsymbiont ability to disperse and adapt to diverse new environments, and that both genetics and environment determine a host's nodular microsymbiont.


Assuntos
Actinomycetales/genética , Evolução Biológica , Raízes de Plantas/microbiologia , Rosales/microbiologia , Actinomycetales/fisiologia , DNA Espaçador Ribossômico/análise , Fixação de Nitrogênio , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Rosales/genética
15.
Chemosphere ; 35(8): 1637-50, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9353904

RESUMO

Columns of an Alfisol under permanent pasture were polluted by repeated additions of pentachlorophenol (PCP) (7 mg l-1) to levels of 102 and 510 mg Kg-1, to simulate a dynamic diffuse pollution. PCP was rapidly sorbed to the soil organic matter, and was only slightly degraded. Measurements of soil microbial biomass-C revealed a 25% decrease in total biomass-C caused by both leaching and PCP toxicity. Microbial biomass-C measurements performed on soil fractions showed that only microorganisms located in the outer compartment of the aggregates were affected. Microorganisms protected by soil micro-aggregates were not affected, suggesting that they were not in contact with PCP, which was thus unavailable for biodegradation. Three gram negative bacterial strains (Si, C3 and C2), able to use PCP as a sole carbon and energy source, were isolated after 0, 1 and 3 months of PCP enrichment respectively, and were identified as Pseudomonas (Si) and Acinetobacter (C3 and C2). In liquid degradation tests, the strains C2 and C3 degraded 60% of PCP within 26 days whereas the Pseudomonas degraded only 25%. A specific immuno-labeling of the three strains permitted to show that repeated PCP additions to soil had a positive, negative or absence of effect on the populations C2, C3 and Si respectively.


Assuntos
Acinetobacter/metabolismo , Inseticidas/metabolismo , Pentaclorofenol/metabolismo , Pseudomonas/metabolismo , Microbiologia do Solo , Acinetobacter/efeitos dos fármacos , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , Contagem de Colônia Microbiana , Meios de Cultura , França , Inseticidas/toxicidade , Pentaclorofenol/toxicidade , Pseudomonas/efeitos dos fármacos , Solo/análise
16.
Appl Environ Microbiol ; 61(6): 2093-8, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7793930

RESUMO

Although the biological conversion of nitrite to nitrate is a well-known process, studies of Nitrobacter populations are hindered by their physiological characteristics. This report describes a new method for detecting and counting Nitrobacter populations in situ with the PCR. Two primers from the 16S rRNA gene were used to generate a 397-bp fragment by amplification of Nitrobacter species DNA. No signal was detected from their phylogenetic neighbors or the common soil bacteria tested. Extraction and purification steps were optimized for minimal loss and maximal purity of soil DNA. The detection threshold and accuracy of the molecular method were determined from soil inoculated with 10, 10(2), or 10(3) Nitrobacter hamburgensis cells per g of soil. Counts were also done by the most-probable-number (MPN)-Griess and fluorescent antibody methods. PCR had a lower detection threshold (10(2) Nitrobacter cells per g of soil) than did the MPN-Griess or fluorescent antibody method. When PCR amplification was coupled with the MPN method, the counting rate reached 65 to 72% of inoculated Nitrobacter cells. Tested on nonsterile soil, this rapid procedure was proved efficient.


Assuntos
Nitrobacter/isolamento & purificação , Contagem de Colônia Microbiana , DNA Bacteriano/genética , DNA Complementar/genética , Nitrobacter/genética , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Microbiologia do Solo
17.
Res Microbiol ; 144(1): 55-67, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8327783

RESUMO

Relationships between bacterial groups nodulating Sesbania rostrata were evaluated through examination of electrophoretic polymorphism of esterases and metabolic enzymes. The following conclusions were drawn: (i) the differentiation of two genomic species within Azorhizobium strains and a group of non-identified strains (probably Rhizobium) was strongly supported by enzyme electrophoresis; (ii) esterases were more electrophoretically polymorphic than metabolic enzymes, since 35 and 11 electrophoretic types, respectively, were detected within the 57 strains studied; (iii) strains isolated from stem or root nodules were genetically very similar and could not be differentiated; (iv) six Azorhizobium strains isolated from plants growing in saline soils could not be grouped separately from the other strains, which might be attributed to the adaptation of azorhizobia to epiphytic conditions; and (v) a comparative study of esterase patterns of azorhizobia showed that strains isolated in the Philippines probably originated in northern Senegal, but did not reveal a clear separation between strains originating from northern and central Senegal.


Assuntos
Esterases/análise , Plantas/microbiologia , Polimorfismo Genético , Rhizobium/enzimologia , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Enzimas/análise , Técnicas In Vitro , Fixação de Nitrogênio
18.
Arch Microbiol ; 157(2): 107-15, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1347989

RESUMO

DNA sequences from the intergenic spacer (IGS) region of the ribosomal operon were amplified by the polymerase chain reaction (PCR) technique using two primers derived from 16S and 23S rRNA conserved sequences. The PCR products, cleaved by 4 base cutting restriction enzymes, were used to differentiate Nitrobacter strains. This method offered a convenient alternative to serological testing for characterization of Nitrobacter isolates and enabled a large number of strains to be genotypically characterized easily and rapidly. This method was successfully used to characterize natural populations of Nitrobacter from various soils and a lake. A diversity was demonstrated in various soils, and in a lake both in freshwater and in sediments. Strains closely related to both WL and LL were found in these ecosystems. It seems that the diversity of Nitrobacter populations was not associated with global environments but may be related to the presence of locally coexisting niches.


Assuntos
DNA Bacteriano/análise , DNA Ribossômico/análise , Nitrobacter/genética , Microbiologia do Solo , Microbiologia da Água , Sequência de Bases , Genótipo , Dados de Sequência Molecular , Nitrobacter/classificação , Sondas de Oligonucleotídeos/química , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/química , RNA Ribossômico 23S/química , Mapeamento por Restrição
19.
Arch Microbiol ; 153(3): 235-40, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2334247

RESUMO

A set of oligonucleotides has been developed to study the competitivity of two Frankia strains in the nodulation of the roots of two host plant species: Alnus glutinosa and Alnus incana. Two 20 mer-oligonucleotides, complementary to highly conserved sequences inside the nifH gene, were used as primers for the polymerase chain reaction (PCR) system in order to amplify microsymbiont DNA extracted from actinorhizae. PCR products were analyzed using two strain-specific 15-mer oligonucleotides identified in the amplified region. Hybridization data indicate that strain ACoN24d is more competitive than strain ArI3 in the nodulation of both hosts.


Assuntos
Actinomycetales/isolamento & purificação , DNA Bacteriano/análise , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos , Actinomycetales/genética , Sequência de Bases , Southern Blotting , DNA Bacteriano/genética , Dados de Sequência Molecular , Plantas , Reação em Cadeia da Polimerase , Especificidade da Espécie
20.
Microb Ecol ; 19(2): 163-70, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24196309

RESUMO

The degree of phenotypic variation of the bacterial strains USDA 125-Sp, USDA 138 and USDA 138-SmBradyrhizobium japonicum a long time after introduction was studied in three experimental fields. A total of 54 phenotypic characters were analyzed by constructing a dendrogram based on an hierarchic classification. Strong similarities (92.6, 94 and 95%) were found between the isolates introduced into soil 8, 10 and 13 years ago and between their respectiveB. japonicum parental clones. The dendrogrammic analysis detected a small amount of phenotypic drift, however, between soil isolates and parental clones belonging to the same serogroup (selective effects were found to have generated 0 to 3.9% variation for the USDA 125-Sp inoculum introduced 8 years ago, and 3.2-3.5% after 10 and 13 years, respectively, for the USDA 138 and USDA 138-Sm bacterial inocula) and within the serogroup 125 soil isolates (2.7%). We found a similar evolution of serogroup 125 isolates when compared with parental clones conserved on slant agar at 4°C. When a drift was observed, the isolates from soil presented a lower activity for several enzymes and lower diversity compared with the parental clones.

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