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1.
J Neurooncol ; 163(2): 345-354, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37266846

ABSTRACT

BACKGROUND: The multidisciplinary management of patients with brain metastases consists of surgical resection, radiation treatment and systemic treatment. Tailoring and timing these treatment modalities is challenging. This study presents real-world data from consecutively treated patients and assesses the impact of all treatment strategies and their relation with survival. The aim is to provide new insights to improve multidisciplinary decisions towards individualized treatment strategies in patients with brain metastases. METHODS: A retrospective consecutive cohort study was performed. Patients with brain metastases were included between June 2018 and May 2020. Brain metastases of small cell lung carcinoma were excluded. Overall survival was analyzed in multivariable models. RESULTS: 676 patients were included in the study, 596 (88%) received radiotherapy, 41 (6%) awaited the effect of newly started or switched systemic treatment and 39 (6%) received best supportive care. Overall survival in the stereotactic radiotherapy group was 14 months (IQR 5-32) and 32 months (IQR 11-43) in patients who started or switched systemic treatment and initially did not receive radiotherapy. In patients with brain metastases without options for local or systemic treatment best supportive care was provided, these patients had an overall survival of 0 months (IQR 0-1). Options for systemic treatment, Karnofsky Performance Score ≥ 70 and breast cancer were prognostic for a longer overall survival, while progressive extracranial metastases and whole-brain-radiotherapy were prognostic for shorter overall survival. CONCLUSIONS: Assessing prognosis in light of systemic treatment options is crucial after the diagnosis of brain metastasis for the consideration of radiotherapy versus best supportive care.


Subject(s)
Brain Neoplasms , Lung Neoplasms , Radiosurgery , Humans , Retrospective Studies , Cohort Studies , Prognosis , Brain Neoplasms/surgery , Lung Neoplasms/pathology , Treatment Outcome
2.
Knee Surg Sports Traumatol Arthrosc ; 30(6): 1976-1989, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35072757

ABSTRACT

PURPOSE: The purpose of this study was to determine and compare the percentage of completely healed meniscal tears after arthroscopic repair combined with anterior cruciate ligament reconstruction (ACLR) for the different vascular zones of the meniscus. METHODS: PubMed, Embase, Web of Science, Cochrane library and Emcare were searched on 19 May 2020 for articles reporting healing rates after arthroscopic meniscal repair with concomitant ACLR for the different meniscal vascular zones as assessed by second-look arthroscopy. Data on meniscal tears were extracted as located in zones 1, 2 or 3, according to the Cooper classification. Studies were graded in quality using a modified Newcastle-Ottawa Scale. Pooled analyses were performed utilizing a random-effects model. Meta-analyses were performed using R version 3.6.2 and SPSS statistical software version 25.0. The study was registered with PROSPERO (ID:CRD42020176175). RESULTS: Ten observational cohort studies met the inclusion criteria, accounting for 758 meniscal tear repairs in total. The pooled overall proportion of healing was 78% (95% CI 72-84%). The mean weighted proportion of healing was 83% (95% CI 76-90%) for studies (n = 10) reporting zone 1 tears and 69% (95% CI 59-79%) for studies (n = 9) reporting zone 2 tears. No study reported healing rates for zone 3 tears. The pooled overall odds ratio was 2.5 (95% CI 1.00-6.02), indicating zone 1 tears as 2.5 times more likely to heal than zone 2 tears. CONCLUSION: This study demonstrates that meniscal tears localized in vascular zone 1 were more likely to heal than those in zone 2. LEVEL OF EVIDENCE: IV.


Subject(s)
Anterior Cruciate Ligament Injuries , Anterior Cruciate Ligament Reconstruction , Cartilage Diseases , Knee Injuries , Tibial Meniscus Injuries , Anterior Cruciate Ligament Injuries/surgery , Arthroscopy , Cartilage Diseases/surgery , Humans , Knee Injuries/surgery , Menisci, Tibial/surgery , Second-Look Surgery , Tibial Meniscus Injuries/surgery
3.
Eur J Paediatr Neurol ; 21(2): 350-357, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27908676

ABSTRACT

BACKGROUND: In non-walking children with severe spasticity, daily care can be difficult and many patients suffer from pain. Selective dorsal rhizotomy (SDR) reduces spasticity in the legs, and therefore has the potential to improve daily care and comfort. AIM: To examine effects of SDR on daily care and comfort in non-walking children with severe spasticity due to different underlying neurological conditions. METHODS: Medical history, changes in daily care and comfort and satisfaction with outcome were assessed retrospectively in non-walking children who underwent SDR in our center, with a mean follow-up of 1y 7m (range 11m-4y 3m). All eligible patients (n = 24, years 2009-2014) were included. RESULTS: Mean age at SDR was 12y 4m (SD 4y 3m, range 2y 8m-19y 3m). Associated orthopaedic problems were frequent. Seven patients underwent scoliosis correction in the same session. Most improvements were reported in dressing (n = 16), washing (n = 12) and comfort (n = 10). Median score for satisfaction was 7 on a scale of 10 (range 1-9). SDR resulted in reduction of spasticity in leg muscles. In nine patients dystonia was recorded post-operatively, mainly in children with congenital malformations and syndromes. INTERPRETATION: SDR is a single event intervention that can improve daily care and comfort in non-walking children with severe spasticity, and can safely be combined with scoliosis correction. Despite the improvements, satisfaction is variable. Careful attention is necessary for risk factors for dystonia, which may be unmasked after SDR.


Subject(s)
Muscle Spasticity/surgery , Patient Care , Patient Comfort , Rhizotomy , Adolescent , Child , Child, Preschool , Dystonia/complications , Female , Follow-Up Studies , Humans , Male , Orthopedic Procedures , Patient Satisfaction , Postoperative Complications , Retrospective Studies , Rhizotomy/adverse effects , Rhizotomy/methods , Scoliosis/surgery , Treatment Outcome , Walking , Young Adult
4.
Eur J Paediatr Neurol ; 20(4): 545-8, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26970946

ABSTRACT

INTRODUCTION: Therapeutic hypothermia improves outcome after perinatal asphyxia. The Ages and Stages Questionnaire is a screening tool to detect neurodevelopmental delay. In this study we examined the outcome of patients with perinatal asphyxia (defined as Apgar score <5 at 10 min, or continued need for resuscitation, or pH < 7.00 in umbilical cord or within one hour after birth) with and without therapeutic hypothermia treatment at the age of four years. METHODS: Cohort study of patients with perinatal asphyxia admitted to the Neonatal Intensive Care Units of the VU University Medical Center, Amsterdam and the Wilhelmina Children's Hospital, Utrecht in the year 2008. Parents were asked to fill out the 48 months Ages and Stages Questionnaire (ASQ). In Wilhelmina Children's Hospital treatment with therapeutic hypothermia was implemented in 2008, in the VU University Medical Center in 2009, providing a historical cohort. RESULTS/DISCUSSION: Twenty-three questionnaires were evaluated. Response rate of questionnaires for the VU Medical Center was 63% (n = 10) and Wilhelmina's Childrens Hospital 93% (n = 13). No significant differences were found in the mean scores between both groups. However, the untreated group scored more frequently under the -2 SD threshold. In the fine motor skills domain the difference was statistically significant (p = 0.031). In the treated group no patients developed cerebral palsy and in the untreated group two patients developed cerebral palsy. CONCLUSION: In this study patients treated with hypothermia tend to have a better neurodevelopmental outcome. No significant differences were found between the two groups, apart from the fine motor skills.


Subject(s)
Asphyxia Neonatorum/therapy , Hypothermia, Induced , Surveys and Questionnaires , Apgar Score , Child , Child, Preschool , Developmental Disabilities/diagnosis , Female , Humans , Infant, Newborn , Male , Motor Skills , Pregnancy , Treatment Outcome
5.
J Intellect Disabil Res ; 55(6): 550-62, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21435067

ABSTRACT

BACKGROUND: Children with cerebral palsy (CP) are at greater risk for a limited intellectual development than typically developing children. Little information is available which children with CP are most at risk. This study aimed to describe the development of non-verbal intellectual capacity of school-age children with CP and to examine the association between the development of non-verbal intellectual capacity and the severity of CP. METHODS: A longitudinal analysis in a cohort study was performed with a clinic-based sample of children with CP. Forty-two children were assessed at 5, 6 and 7 years of age, and 49 children were assessed at 7, 8 and 9 years of age. Non-verbal intellectual capacity was assessed by Raven's Coloured Progressive Matrices (RCPM). Severity of CP was classified by the Gross Motor Function Classification System, type of motor impairment and limb distribution. manova for repeated measurements was used to analyse time effects and time × group effects on both RCPM raw scores and RCPM intelligence quotient scores. RESULTS: The development of non-verbal intellectual capacity was characterised by a statistically significant increase in RCPM raw scores but no significant change in RCPM intelligence quotient scores. The development of RCPM raw scores was significantly associated with the severity of CP. Children with higher levels of gross motor functioning and children with spastic CP showed greater increase in raw scores than children with lower levels of gross motor functioning and children with dyskinetic CP. CONCLUSIONS: Children with CP aged between 5 and 9 years show different developmental trajectories for non-verbal intellectual capacity, which are associated with the severity of CP. The development of non-verbal intellectual capacity in children with less severe CP seems to resemble that of typically developing children, while children with more severe CP show a limited intellectual development compared to typically developing children.


Subject(s)
Cerebral Palsy/diagnosis , Cerebral Palsy/psychology , Intellectual Disability/diagnosis , Intellectual Disability/psychology , Intelligence Tests/statistics & numerical data , Problem Solving , Cerebral Palsy/rehabilitation , Child , Child, Preschool , Cohort Studies , Disability Evaluation , Female , Humans , Intellectual Disability/rehabilitation , Longitudinal Studies , Male
6.
Neuropediatrics ; 41(5): 209-16, 2010 Oct.
Article in English | MEDLINE | ID: mdl-21210336

ABSTRACT

INTRODUCTION: Selective dorsal rhizotomy (SDR) is an effective treatment for reducing spasticity and improving gait in children with spastic cerebral palsy. Data concerning muscle activity changes after SDR treatment are limited. PATIENTS AND METHODS: In 30 children who underwent SDR a gait analysis was performed before and 12-24 months postoperatively. Subjects walked on a 10-m walkway at comfortable walking speed. Biplanar video was registered and surface EMG was recorded. Sagittal knee angles were measured from video and observational gait assessments were performed using the Edinburgh gait assessment scale (EGAS). RESULTS: The EGAS significantly improved after SDR (p<0.001). There were significant improvements of the knee angle kinematics (p<0.001). Only slight changes in EMG activity were observed. The activity of the m. gastrocnemius (GM) decreased and a late peak appeared in stance, the activity of the m. semitendinosus (ST) increased in stance. The activity of the m. rectus femoris (RF) decreased in swing. CONCLUSION: SDR improved overall gait performance but EMG changes were only slight. Better timing of the GM in stance and reduced activity of RF in swing may have increased knee flexion in swing. Reduced hamstrings spasticity may have led to postural instability in the hip.


Subject(s)
Cerebral Palsy/surgery , Gait/physiology , Rhizotomy , Adolescent , Biomechanical Phenomena/physiology , Cerebral Palsy/physiopathology , Child , Child, Preschool , Electromyography , Female , Humans , Knee/physiopathology , Male , Muscle, Skeletal/physiopathology , Treatment Outcome , Video Recording
8.
Early Hum Dev ; 84(9): 605-11, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18448276

ABSTRACT

BACKGROUND: Assessment of general movements (GMs) at three months is considered useful for prediction of adverse neurological outcome in high risk infants. AIMS: To study the prevalence of abnormal GMs in infants born from women with early-onset hypertensive disorders of pregnancy and the association of GMs with neurodevelopmental outcome at one year. STUDY DESIGN: Prospective study, part of a randomised controlled trial of pre-birth management strategies. SUBJECTS: Infants born from women with early-onset hypertensive disorders of pregnancy. OUTCOME MEASURES: GMs observation and neurological examination at term and three months corrected age; at one year neurological examination and Bayley Scales of Infant Development. RESULTS: From 216 women included, 175 of 178 surviving infants (mean gestational age 31.6 weeks [SD 2.3], mean birth weight 1346 grams [SD 458]), were examined at three months. At term age normal, mildly abnormal and definitely abnormal GMs were observed in 54%, 36% and 10% respectively; and at three months in 47%, 40% and 13%. Mildly or definitely abnormal GMs at three months were not associated with abnormal neurological examination at one year, however, they were associated with delayed psychomotor development at one year (p = 0.01). CONCLUSIONS: In this prospective study, including small for gestational age, preterm infants about half of them did not have normal GMs at term and three months. There was no association of GMs at term nor three months with neurological outcome at one year, but there was a significant association of GMs at three months with one year psychomotor development.


Subject(s)
Child Development/physiology , Hypertension, Pregnancy-Induced/physiopathology , Infant Behavior/physiology , Mothers , Movement/physiology , Adult , Female , Fetal Growth Retardation/diagnosis , Fetal Growth Retardation/epidemiology , Fetal Growth Retardation/physiopathology , Humans , Hypertension, Pregnancy-Induced/epidemiology , Infant , Infant, Newborn , Male , Netherlands/epidemiology , Neurologic Examination , Pregnancy , Prevalence , Prospective Studies , Psychomotor Disorders/diagnosis , Psychomotor Disorders/epidemiology , Psychomotor Disorders/physiopathology , Time Factors
9.
Child Care Health Dev ; 33(5): 604-10, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17725783

ABSTRACT

BACKGROUND: The Measure of Processes of Care (MPOC) is a 56-item self-administered measure designed to examine what parents of a child with a chronic health problem think of the services they and their child receive, and to measure the extent to which these services are family-centred. Reliability and validity of the MPOC were established in prior studies. The aim of the present study was to assess the 1-year stability of the MPOC to justify its use as an evaluative tool. METHODS: Nine paediatric rehabilitation centres in the Netherlands participated in this short longitudinal survey study. Subjects were 205 parents (response rate 74.8%) of children aged 1-18 years who received care in one of the participating paediatric rehabilitation centres. All subjects filled out two MPOCs with a 1-year interval. RESULTS: All correlations between the scale scores of the MPOC at the first and second administration were relatively high and significant (range: 0.443-0.609, all P < 0.001), demonstrating high inter-individual stability. However, all mean scale scores, except for Providing General Information, significantly reduced after 1 year. CONCLUSIONS: The MPOC has a moderate 1-year stability. However, because of its tendency to score lower when repeated after 1 year, its use as an evaluative follow-up instrument to assess the effectiveness of a programme intervention is restricted.


Subject(s)
Child Health Services/statistics & numerical data , Disabled Children/rehabilitation , Health Care Surveys/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Process Assessment, Health Care/statistics & numerical data , Adolescent , Child , Child Health Services/standards , Child, Preschool , Female , Humans , Infant , Male , Netherlands , Parents/psychology , Process Assessment, Health Care/standards
10.
Neuropediatrics ; 38(2): 71-7, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17712734

ABSTRACT

OBJECTIVE: The aim of this report is to describe the motor outcome in one year-old children who were born at full-term with perinatal hypoxic-ischemic encephalopathy (HIE). Relationships between motor ability tests and neurological examination at one year, and between these tests and neonatal brain magnetic resonance imaging (MRI) were investigated. PARTICIPANTS AND METHODS: 32 surviving children, born full-term with perinatal HIE, are included in this report. All children had a neonatal MRI. At one year, motor ability was assessed with the Alberta Infant Motor Scale and the Bayley Scales of Infant Development (2nd version). Neurological examinations included the neurological optimality score (NOS). RESULTS: At one year, 14 children (44%) had normal motor ability, nine (28%) had mildly delayed, and nine had significantly delayed motor ability. The NOS ranged from 14.6-27 points. All children with normal motor ability had (near) optimal NOS, however, not all children with high NOS had normal motor ability. Eleven children (34%) had normal neonatal MRI; at one year, six of them had normal, and five had mildly delayed motor ability. Eight children with normal motor ability showed abnormalities on neonatal MRI. CONCLUSION: Neonatal brain MRI does not predict motor outcome at one year. Motor ability tests and neurological examinations should be used in a complementary manner to describe outcome after HIE.


Subject(s)
Child Development/physiology , Hypoxia-Ischemia, Brain/physiopathology , Hypoxia-Ischemia, Brain/psychology , Motor Activity/physiology , Aptitude/physiology , Female , Follow-Up Studies , Humans , Hypoxia-Ischemia, Brain/pathology , Infant , Infant, Newborn , Magnetic Resonance Imaging , Male , Prospective Studies , Term Birth
11.
Dev Neurorehabil ; 10(3): 193-204, 2007.
Article in English | MEDLINE | ID: mdl-17564860

ABSTRACT

PURPOSE: Generally, there is a lack of knowledge whether and how parent-identified problems, treatment goals and treatment activities are tuned in the treatment of children with cerebral palsy. This study aimed to observe whether parent-identified problems and treatment goals were documented ('transparency' of the rehabilitation process), and to examine the relationship ('tuning') of parent-identified problems to treatment goals and to treatment activities of children with cerebral palsy in pediatric rehabilitation in the Netherlands. METHOD: Five school-aged subjects with cerebral palsy were observed in detail during physical, occupational, and speech therapy, and their written reports were studied. Parent-identified problems, treatment goals, and treatment activities were linked to the ICF components, domains and categories and the amount of agreement was determined by code comparison. RESULTS: Only two children with a total of six parent-identified problems could be documented. Forty-five treatment goals were identified and 72 treatment activities were observed. The analyses indicated some tuning of parent-identified problems, goals and activities in all subjects, but only four of the treatment activities were perfectly tuned to treatment goals as well as to parent-identified problems. CONCLUSIONS: We conclude that transparency and tuning of the pediatric treatment process described in the present study could be improved substantially. Several suggestions for improving the transparency and tuning of the treatment process are discussed.


Subject(s)
Cerebral Palsy/rehabilitation , Needs Assessment , Cerebral Palsy/physiopathology , Child , Child, Preschool , Community Participation , Comprehensive Health Care , Goals , Humans , Occupational Therapy , Outcome Assessment, Health Care , Parents , Patient Care Planning , Patient Care Team , Physical Therapy Modalities , Professional-Family Relations , Speech Therapy , Treatment Outcome
12.
Child Care Health Dev ; 33(2): 196-205, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17291324

ABSTRACT

AIM: The importance of family-centred care and services has been increasingly emphasized in paediatric rehabilitation. One aspect of family-centred care is parent involvement in their child's treatment. The aims of this study were (1) to describe how, and to what extent parents are involved in the paediatric rehabilitation treatment process in the Netherlands; (2) to determine the level of parents' satisfaction about the services they and their child have received; and (3) to describe what ideas parents have to enhance their involvement in the treatment process. METHODS: A total of 679 parents of children aged 1-20 years who participated in our longitudinal study on family centred care in the Netherlands. The children had various diagnoses and were treated in nine out of 23 Dutch paediatric rehabilitation centres. A random sample of 75 parents was interviewed within 4 weeks after completion of the Measure of Processes of Care and the Client Satisfaction Questionnaire. A Quality of Care cycle with six stages was used to structure the evaluation. RESULTS: The data showed that parents are involved in all stages of their child's rehabilitation process in various ways. The average level of parent satisfaction about the services received was high. According to the interviewed parents, the communication between professionals and parents, parents' involvement in goal setting, and parents' involvement in treatment could be improved upon. CONCLUSION: Parents are to a large extent involved in all stages of the treatment process in Dutch paediatric rehabilitation settings. Although parents valued the services received, they suggested various ways to enhance parent participation.


Subject(s)
Child Health Services , Consumer Behavior , Family Health , Parents/psychology , Professional-Family Relations , Rehabilitation/organization & administration , Adolescent , Adult , Child , Child Health Services/organization & administration , Child, Preschool , Female , Humans , Infant , Longitudinal Studies , Male , Middle Aged , Netherlands , Patient Satisfaction , Process Assessment, Health Care , Surveys and Questionnaires
13.
Child Care Health Dev ; 30(5): 529-39, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15320929

ABSTRACT

AIM: The objective was to validate the Dutch translation of the Canadian measure of processes of care (MPOC) questionnaire for use in children's rehabilitation centres in the Netherlands. MPOC consists of 56 items (assessing five domains) and was designed to find out what parents of children with chronic health problems think of the services they and their child receive and to measure the extent to which these services are family-centred. METHODS: The Canadian validation procedures were followed, consisting of construct and concurrent validation and reliability analyses. Participants were parents of 427 children aged 1-18 years recruited through nine children's rehabilitation centres in the Netherlands. RESULTS: The construct validity of the Dutch version of MPOC (MPOC-NL) was examined with confirmative analyses of the scale structure. These analyses all supported the construct validity of MPOC-NL. MPOC-NL showed adequate internal consistency, with Cronbach's alpha ranging from 0.80 to 0.95. The intraclass correlation coefficients (ICCs) ranged from 0.79 to 0.94, which demonstrated good stability of MPOC-NL. The Spearman correlations between MPOC-NL scores and satisfaction questions ranged from 0.39 to 0.73, and thus supported the construct validity of MPOC-NL. Correlations between MPOC-NL scores and a question about parents' stress in relation to services received were moderately negative (r(s) = -0.28 to -0.39). CONCLUSION: The construct and concurrent validity of MPOC-NL was shown by confirmative analyses of the original Canadian scale structure, and by modest Spearman correlations between MPOC-NL scores and satisfaction and stress variables. MPOC-NL is internally consistent and reliable.


Subject(s)
Child Health Services/standards , Developmental Disabilities/rehabilitation , Surveys and Questionnaires , Adolescent , Child , Child, Preschool , Chronic Disease , Female , Humans , Infant , Long-Term Care , Male , Netherlands , Parents/psychology , Patient Satisfaction , Reproducibility of Results , Surveys and Questionnaires/standards , Translations
14.
Neuropediatrics ; 34(2): 72-6, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12776227

ABSTRACT

Presently, prognosis of infants with perinatal hypoxia-ischaemia is estimated using the Sarnat scale, which combines clinical evaluation and electroencephalography, in combination with magnetic resonance imaging (MRI) and or evoked potentials. While the value of conventional MRI is limited during the first week of life, diffusion-weighted MRI demonstrates effects of acute cerebral ischaemia within hours of onset. However, the exact value of diffusion MRI in the prognosis of infants with hypoxia-ischaemia has to be established in larger follow-up studies. In this report we describe 5 term (post-conceptional age 40 1/7 to 41 2/7 week) neonates with severe hypoxia-ischaemia and a characteristic pattern of diffusion changes. T 1 -weighted images showed a hyperintense cortical signal in only one case and extensive hyperintensity in the basal nuclei in all 5 cases. T 2 -weighted images showed nearly complete loss of cortical delineation in three cases. Increased signal on diffusion-weighted images was seen throughout all cortical and subcortical areas while the cerebellum remained normal. This pattern, which we refer to as the "white cerebrum", is most readily apparent on coronal images. The apparent diffusion coefficient (ADC) was calculated and compared to that of four control infants. In the cortex ADC values were lowered (0.70 +/- 0.17 micro m 2/msec [mean +/- standard deviation (SD)]; controls [n = 4]: 1.18 +/- 0.02 micro m 2/msec) as compared to values of ADC in the cerebellum (1.31 +/- 0.06 micro m 2/msec [mean +/- SD]; controls [n = 4]: 1.25 +/- 0.06 micro m 2/msec). All infants died in the perinatal period. In summary, the "white cerebrum" on diffusion-weighted MRI indicates severe neonatal hypoxia-ischaemia and is the counterpart of the white cerebellum on CT.


Subject(s)
Diffusion Magnetic Resonance Imaging , Hypoxia-Ischemia, Brain/congenital , Hypoxia-Ischemia, Brain/pathology , Telencephalon/pathology , Female , Humans , Infant, Newborn , Male , Predictive Value of Tests , Prognosis , Severity of Illness Index
15.
Appl Environ Microbiol ; 65(11): 5082-8, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10543826

ABSTRACT

In order to exploit the ability of anaerobic bacteria to degrade certain contaminants for bioremediation of polluted subsurface environments, we need to understand the mechanisms by which such bacteria partition between aqueous and solid phases, as well as the environmental conditions that influence partitioning. We studied four strictly anaerobic bacteria, Desulfomonile tiedjei, Syntrophomonas wolfei, Syntrophobacter wolinii, and Desulfovibrio sp. strain G11, which theoretically together can constitute a tetrachloroethylene- and trichloroethylene-dechlorinating consortium. Adhesion of these organisms was evaluated by microscopic determination of the numbers of cells that attached to glass coverslips exposed to cell suspensions under anaerobic conditions. We studied the effects of the growth phase of the organisms on adhesion, as well as the influence of electrostatic and hydrophobic properties of the substratum. Results indicate that S. wolfei adheres in considerably higher numbers to glass surfaces than the other three organisms. Starvation greatly decreases adhesion of S. wolfei and Desulfovibrio sp. strain G11 but seems to have less of an effect on the adhesion of the other bacteria. The presence of Fe(3+) on the substratum, which would be electropositive, significantly increased the adhesion of S. wolfei, whereas the presence of silicon hydrophobic groups decreased the numbers of attached cells of all species. Measurements of transport of cells through hydrophobic-interaction and electrostatic-interaction columns indicated that all four species had negatively charged cell surfaces and that D. tiedjei and Desulfovibrio sp. strain G11 possessed some hydrophobic cell surface properties. These findings are an early step toward understanding the dynamic attachment of anaerobic bacteria in anoxic environments.


Subject(s)
Bacteria, Anaerobic/physiology , Bacterial Adhesion/physiology , Tetrachloroethylene/pharmacokinetics , Trichloroethylene/pharmacokinetics , Anaerobiosis , Biodegradation, Environmental , Desulfovibrio/physiology , Environmental Pollution , Glass , Iron , Silicones , Species Specificity , Surface Properties
16.
Appl Environ Microbiol ; 64(7): 2432-8, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9647811

ABSTRACT

Phenol is a man-made as well as a naturally occurring aromatic compound and an important intermediate in the biodegradation of natural and industrial aromatic compounds. Whereas many microorganisms that are capable of aerobic phenol degradation have been isolated, only a few phenol-degrading anaerobic organisms have been described to date. In this study, three novel nitrate-reducing microorganisms that are capable of using phenol as a sole source of carbon were isolated and characterized. Phenol-degrading denitrifying pure cultures were obtained by enrichment culture from anaerobic sediments obtained from three different geographic locations, the East River in New York, N.Y., a Florida orange grove, and a rain forest in Costa Rica. The three strains were shown to be different from each other based on physiologic and metabolic properties. Even though analysis of membrane fatty acids did not result in identification of the organisms, the fatty acid profiles were found to be similar to those of Azoarcus species. Sequence analysis of 16S ribosomal DNA also indicated that the phenol-degrading isolates were closely related to members of the genus Azoarcus. The results of this study add three new members to the genus Azoarcus, which previously comprised only nitrogen-fixing species associated with plant roots and denitrifying toluene degraders.


Subject(s)
Gram-Negative Facultatively Anaerobic Rods/isolation & purification , Gram-Negative Facultatively Anaerobic Rods/metabolism , Phenol/metabolism , Biodegradation, Environmental , DNA, Bacterial/genetics , Gram-Negative Facultatively Anaerobic Rods/ultrastructure , Microscopy, Electron , Phylogeny , RNA, Ribosomal, 16S/genetics
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