Repository corticotrophin injection exerts direct acute effects on human B cell gene expression distinct from the actions of glucocorticoids.

Repository corticotrophin injection (RCI, H.P Acthar® gel) has been approved for use in the management of multiple autoimmune and inflammatory diseases for more than a half-century, but its mechanism of action is not well understood. We used RNA-Seq methods to define RCI-regulated mRNAs in cultured human B cells under conditions of activation by interleukin (IL)-4 and CD40 ligand. Following IL-4/CD40L activation and RCI treatment we found up-regulation of 115 unique mRNA transcripts and down-regulation of 80 unique mRNAs. The effect on these RNA levels was dose-dependent for RCI and was distinct from changes in mRNA expression induced by treatment with a potent synthetic glucocorticoid. RCI down-regulated mRNAs were observed to include a significant over-representation of genes critical for B cell proliferation under activating conditions. These data confirm that RCI exerts direct effects on human B cells to modulate mRNA expression in specific pathways of importance to B cell function and that, at the molecular level, the effects of RCI are distinct from those exerted by glucocorticoids.

Immunomodulatory effects of H.P. Acthar Gel on B cell development in the NZB/W F1 mouse model of systemic lupus erythematosus.

H.P. Acthar Gel® (Acthar) is a highly purified repository gel preparation of adrenocorticotropic hormone (ACTH1-39), a melanocortin peptide that can bind and activate specific receptors expressed on a range of systemic lupus erythematosus (SLE)-relevant target cells and tissues. This study was performed to evaluate the effects of Acthar in a mouse model of SLE, using an F1 hybrid of the New Zealand Black and New Zealand White strains (NZB/W F1). Twenty-eight week old NZB/W F1 mice with established autoimmune disease were treated with Acthar, Placebo Gel (Placebo), or prednisolone and monitored for 19 weeks. Outcomes assessed included disease severity (severe proteinuria, ≥ 20% body weight loss, or prostration), measurement of serial serum autoantibody titers, terminal spleen immunophenotyping, and evaluation of renal histopathology. Acthar treatment was linked with evidence of altered B cell differentiation and development, manifested by a significant reduction in splenic B cell follicular and germinal center cells, and decreased levels of circulating total and anti-double-stranded DNA (IgM, IgG, and IgG2a) autoantibodies as compared with Placebo. Additionally, Acthar treatment resulted in a significant decrease of proteinuria, reduced renal lymphocyte infiltration, and attenuation of glomerular immune complex deposition. These data suggest that Acthar diminished pathogenic autoimmune responses in the spleen, peripheral blood, and kidney of NZB/W F1 mice. This is the first preclinical evidence demonstrating Acthar's potential immunomodulatory activity and efficacy in a murine model of systemic lupus erythematosus.

In vitro inhibition of ETEC K88 adhesion by pea hulls and of LT enterotoxin binding by faba bean hulls.

Enterotoxigenic Escherichia coli (ETEC) expressing K88 (F4) adhesins are associated with post-weaning diarrhoea in piglets. Different grain fractions from pea (Pisum sativum) and faba bean (Vicia faba) were tested in vitro for their capacity to counteract aetiological factors, which contribute to the development of diarrhoea. In detail, adhesion of E. coli O149:K91:K88ac (ETEC K88ac) to grain legume products, intended to impair the colonization of the host, was studied as well as interference with receptor binding of the pathogen's heat-labile enterotoxin LT, intended to reduce toxin-inflicted gut cell damage. When comparing different pea and faba bean products tested for their binding capacity of ETEC K88ac, especially pea hulls, but also whole pea meal, starch-enriched and protein-enriched pea meal, and digestion-resistant pea hull and meal fractions showed a higher binding of ETEC K88ac than faba bean products. In contrast to the ETEC K88ac adhesion results, bean hulls proved more effective than pea hulls in preventing GM1 receptor binding of LT. Previous small intestinal segment perfusion experiments we performed with ETEC K88ac-challenged piglets indicated that both pea and bean hulls have the potential for successful application in diarrhoea prophylaxis and treatment, which is in agreement with and refined by our detection of their different modes of functioning.

F2-isoprostane generation in isolated ferret lungs after oxidant injury or ventilated ischemia.

Pulmonary edema develops when pulmonary blood flow is interrupted, then restored. Because the lung is not always hypoxic when ischemic, mechanisms of pulmonary ischemia-reperfusion injury are likely to differ from systemic organs, where reactive oxygen species generated during reperfusion mediate organ dysfunction. We previously showed that pulmonary vascular permeability of isolated ferret lungs increased prior to reperfusion, if ventilation was maintained while blood flow was impaired. To determine whether reactive oxygen metabolites generated during ischemia mediated ischemic injury, we measured tissue levels of F2-isoprostanes as an index of lipid peroxidation, 30 min after administration of glucose (5 mM)-glucose oxidase (GOX, 0.1 U/ml), or after short (45 min) or long (180 min) ventilated ischemia, in isolated ferret lungs. Osmotic reflection coefficient for albumin (sigma alb), an estimate of vascular protein permeability, was measured in the same lungs. Tissue F2-isoprostanes increased 375% after exposure to glucose-GOX in association with a 42% decrease in sigma alb, and administration of catalase (CAT, 100,000 U) and superoxide dismutase (SOD, 25,000 U) completely attenuated this lipid peroxidation. In contrast, tissue F2-isoprostanes increased only 60% following 45 min of ischemia, then did not increase additionally. sigma alb was not altered by 45 min of ischemia, but decreased 72% following 180 min of ischemia. CAT+SOD did not alter F2-isoprostane formation during ischemia, but partially attenuated vascular injury. These results suggest that tissue levels of F2-isoprostanes reflect lung lipid peroxidation, but that F2-isoprostane generation does not directly increase vascular permeability following ventilated pulmonary ischemia.

Encouraging initial response of restless legs syndrome to pramipexole.

Restless legs syndrome (RLS) is a common condition that results in uncomfortable sensations and an urge to move the limbs. Two centers tested a new dopamine agonist, pramipexole, in 23 patients with RLS in a time-limited, open-label, clinical trial. After 4 weeks or more, 19 patients reported significant improvement as assessed by the short International Restless Legs Syndrome Study Group questionnaire (p < 0.0001). These encouraging preliminary results justify larger, controlled trials for pramipexole in patients with RLS.

Cocaine effects on digital blood flow and diffusing capacity for carbon monoxide among chronic cocaine users.

PURPOSE: To determine the acute effects of intravenous (i.v.) cocaine on primarily digital skin blood flow and diffusion capacity for carbon monoxide (CO), and secondarily on subjective and cardiovascular measures. PATIENTS AND METHODS: A double-blind, Latin-square, placebo-controlled, dose-response study was conducted in an inpatient general clinical research center and clinical pharmacology unit of a university teaching hospital. Twelve adult males with histories of illicit drug use including i.v. cocaine received 0, 25, and 50 mg of i.v. cocaine given as 1-minute infusions, on 3 consecutive test days. Digital cutaneous blood flow was determined via laser doppler flowmetry and skin temperature. Diffusing capacity for carbon monoxide (DCO) was measured with standard techniques. Subjective responses were measured by oral report of a numerical ranking of strength of drug effect. Heart rate and blood pressure responses were measured by electronic sphygmomanometer. RESULTS: A maximal decrease in skin blood flow occurred at 2 to 3 minutes after infusion, and was not distinguished among drug conditions. Blood flow returned to baseline more rapidly after placebo than after cocaine: 7 minutes (placebo), 35 minutes (25 mg cocaine), 50 minutes (50 mg cocaine). Skin temperature decreased by 1.25 degrees C after placebo and by 2.75 and 3.25 degrees C after 25 and 50 mg of cocaine, respectively. DCO changed by -1.02 (mean) +/- 0.25 (standard deviation), 0.16 +/- 1.22, and 0.21 +/- 1.63 ml/min/mm Hg following placebo, 25, and 50 mg of cocaine, respectively. Typical subjective, chronotropic, and pressor responses to cocaine were demonstrated, and these occurred in close temporal relationship to digital blood flow and skin temperature responses. CONCLUSIONS: The digital cutaneous circulation is highly sensitive to vasoconstrictor effects of cocaine. Pulmonary blood volume tends to be preserved after i.v. cocaine. Subjective effects and cardiovascular responses occur in concert with peripheral blood flow changes. The peripheral vasoconstrictor effects have implications for cocaine users with concurrent vasospastic or vasculopathic disorders.

Dopaminergic agents in restless legs syndrome and periodic limb movements of sleep: response and complications of extended treatment in 49 cases.

Restless legs syndrome (RLS) is a common neurosensorimotor disorder that presents with paresthesias, sleep disturbances and, in most cases, periodic limb movements of sleep (PLMS). Although many treatments have been described, interest has recently been focused on dopaminergic mechanisms of etiology and treatment. The dopamine agonists L-dopa/carbidopa, bromocriptine mesylate or both were initiated in 49 patients with RLS/PLMS who sought consultation at a sleep disorders center. This retrospective study describes the symptoms, time course of response and complications in 36 men and 13 women with a mean age of 53.9 years. Only 47 of the patients were available for extended follow-up. The most common presenting complaints were the sensation of restless legs and sleep maintenance insomnia lasting over 20 years. In the extended follow-up group of 47, four failed to respond to L-dopa or bromocriptine, five discontinued treatment because of side effects and two reported loss of therapeutic effect within the first month. Between month one and six, only three additional subjects discontinued treatment. At a mean follow-up of 283 days (SD 316), 33 patients continued on L-dopa/carbidopa at a mean bedtime dose of 160 mg L-dopa (SD 300). Treatment-emergent morning leg restlessness developed in eight patients, seven of whom required daytime medication for relief. Other side effects, generally nausea, occurred in only eight of 43 patients. Psychiatric side effects of dyskinesia were not seen. The > 70% long-term response is comparable to other studies in the literature.

The functional approach to the care of the elderly: a conceptual framework.

A conceptual framework that is based on the biopsychosocial model and focuses on functional status is proposed for the understanding and teaching of the functional approach to health care. Functional status can be viewed as the composition of various biologic, psychologic, and social capabilities that are integrated in order to perform the activities necessary to ensure an individual's well-being. When functional status is threatened by aging or by disease-related deficits, a compensatory response is generated by mobilizing reserve resources/capabilities in an effort to maintain functional status. Since the aging process is characterized by the acquisition of multiple age- and disease-related deficits, primary care providers need to appropriately detect functional impairments through multidimensional assessment and orchestrate compensatory responses in an effort to restore, maximize, and maintain functional status and independence for as long as possible.

The role of lumbar puncture in the evaluation of dementia: the Durham Veterans Administration/Duke University Study.

The use of lumbar puncture (LP) and cerebrospinal fluid (CSF) analysis in the routine, initial evaluation of patients with dementia continues to be questioned. This is especially true in the investigation of infectious causes of dementia. To explore this question further, the authors performed a retrospective analysis of 672 hospitalized patients specifically evaluated for dementia. LP and CSF analysis were performed on 402 patients (60 per cent); routine bacteriologic, acid-fast, and fungal cultures were also obtained for 333 of these patients. Most patients were white (64 per cent) and male (63 per cent), their mean age being 66 +/- 11 years. Four patients were diagnosed as having meningitis--two with Cryptococcus neoformans, one with apparent Mycobacterium tuberculosis, and one with coagulase-positive Staphylococcus aureus. These patients were characterized by a subacute change in mental status, fever or meningismus, and CSF pleocytosis with abnormal CSF chemistries. None of the patients were found to have newly diagnosed neurosyphilis. The authors conclude that LP and CSF analysis should not be part of the routine evaluation of patients with dementia and should be performed only in the presence of such indications as a subacute duration of dementia, fever, and signs of meningeal irritation.

Protective effects of intravascular pressure and nitric oxide in ischemic lung injury.

Cessation of blood flow during ischemia will decrease both distending and shear forces exerted on endothelium and may worsen ischemic lung injury by decreasing production of nitric oxide (NO), which influences vascular barrier function. We hypothesized that increased intravascular pressure (Piv) during ventilated ischemia might maintain NO production by increasing endothelial stretch or shear forces, thereby attenuating ischemic lung injury. Injury was assessed by measuring the filtration coefficient (Kf) and the osmotic reflection coefficient for albumin (sigmaalb) after 3 h of ventilated (95% O2-5% CO2; expiratory pressure 3 mmHg) ischemia. Lungs were flushed with physiological salt solution, and then Piv was adjusted to achieve High Piv (mean 6.7 +/- 0.4 mmHg, n = 15) or Low Piv (mean 0.83 +/- 0.4 mmHg, n = 10). NG-nitro-L-arginine methyl ester (L-NAME; 10(-5) M, n = 10), NG-nitro-D-arginine methyl ester (D-NAME; 10(-5) M, n = 11), or L-NAME (10(-5) M)+L-arginine (5 x 10(-4) M, n = 6) was added at the start of ischemia in three additional groups of lungs with High Piv. High Piv attenuated ischemic injury compared with Low Piv (sigmaalb 0.67 +/- 0.04 vs. 0. 35 +/- 0.04, P < 0.05). The protective effect of High Piv was abolished by L-NAME (sigmaalb 0.37 +/- 0.04, P < 0.05) but not by D-NAME (sigmaalb 0.63 +/- 0.07). The effects of L-NAME were overcome by an excess of L-arginine (sigmaalb 0.56 +/- 0.05, P < 0.05). Kf did not differ significantly among groups. These results suggest that Piv modulates ischemia-induced barrier dysfunction in the lung, and these effects may be mediated by NO.

Effects of oxygen tension and glucose concentration on ischemic injury in ventilated ferret lungs.

In the ventilated ischemic lung, oxygen tension will increase at a time when glucose depletion may impair antioxidant defenses, thereby predisposing the lung to injury mediated by oxygen radicals. In the unventilated ischemic lung, however, glucose depletion in the setting of low oxygen tension may decrease production of ATP, leading to injury by a different mechanism. In this study, we evaluated the role of both oxygen tension and glucose concentration on ischemic injury in isolated ferret lungs. Injury, defined as an increase in vascular permeability, was assessed by measurement of filtration coefficient (Kf) and osmotic reflection coefficient for albumin (sigma alb) after 3 h of normothermic (37 degrees C) ischemia without reperfusion. Lungs were ventilated with either 95% O2-5% CO2 or 0% O2-5% CO2. The vasculature was flushed with physiological salt solution containing either 15 mM glucose (hyperoxia-glucose, anoxia-glucose), 15 mM sucrose (hyperoxia-sucrose, anoxia-sucrose), or no substrate (hyperoxia-no substrate, anoxia-no substrate) (n = 6 for each condition). Kf and sigma alb in hyperoxia-no substrate group did not differ from values in minimally ischemic normoxic normoglycemic ferret lungs. Without glucose, ischemic injury was worse in anoxic than in hyperoxic lungs. With glucose, ischemic injury was worse in hyperoxic than in anoxic lungs. Glucose exacerbated injury in hyperoxic, but not anoxic, lungs. These results indicate that ischemic injury in these lungs depended on both oxygen tension and glucose concentration and suggest that both oxygen radical generation and ATP depletion during ischemia may contribute to the development of this injury.

Separate effects of ischemia and reperfusion on vascular permeability in ventilated ferret lungs.

In systemic organs, ischemia-reperfusion injury is thought to occur during reperfusion, when oxygen is reintroduced to hypoxic ischemic tissue. In contrast, the ventilated lung may be more susceptible to injury during ischemia, before reperfusion, because oxygen tension will be high during ischemia and decrease with reperfusion. To evaluate this possibility, we compared the effects of hyperoxic ischemia alone and hyperoxic ischemia with normoxic reperfusion on vascular permeability in isolated ferret lungs. Permeability was estimated by measurement of filtration coefficient (Kf) and osmotic reflection coefficient for albumin (sigma alb), using methods that did not require reperfusion to make these measurements. Kf and sigma alb in control lungs (n = 5), which were ventilated with 14% O2-5% CO2 after minimal (15 +/- 1 min) ischemia, averaged 0.033 +/- 0.004 g.min-1.mmHg-1.100 g-1 and 0.69 +/- 0.07, respectively. These values did not differ from those reported in normal in vivo lungs of other species. The effects of short (54 +/- 9 min, n = 10) and long (180 min, n = 7) ischemia were evaluated in lungs ventilated with 95% O2-5% CO2. Kf and sigma alb did not change after short ischemia (Kf = 0.051 +/- 0.006 g.min-1.mmHg-1.100 g-1, sigma alb = 0.69 +/- 0.07) but increased significantly after long ischemia (Kf = 0.233 +/- 0.049 g.min-1 x mmHg-1 x 100 g-1, sigma alb = 0.36 +/- 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Common sleep disorders in the elderly: diagnosis and treatment.

Insomnia and daytime sleepiness in an elderly patient may be a normal consequence of aging, the result of a primary sleep disorder, or an adverse effect of medication or medical illness. Effective management requires a differential diagnosis. Adjustment sleep disorder, primary snoring, inadequate sleep hygiene, and mood disorders are common in the aged. The physician needs to review the patient history, including stressful events, medications, medical illness, and the possible presence of a psychiatric disorder. Treatment often involves behavioral changes and conservative use of medications, including antidepressants or benzodiazepines.

Insomnia. Use of a 'decision tree' to assess and treat.

Insomnia, a remarkably common disturbance in a basic biologic function, arises from multiple psychological, physiologic, and environmental factors. Transient insomnia usually resolves spontaneously. Short-term insomnia is usually normalized by coping with acute changes in a medical condition or a relationship. In patients with insomnia caused by stressful life events, a short (ie, 10 days or less) course of a short- or intermediate-acting benzodiazepine hypnotic may be indicated. Long-term insomnia deserves comprehensive evaluation. Psychiatric disorders are common in patients with long-term insomnia. In patients over age 50, intrinsic sleep disorders are more prevalent. Behavioral therapy, including improved sleep hygiene, stimulus-control techniques, and sleep-restriction therapy, is preferred in the management of long-term insomnia. Pharmacotherapy (eg, low-dose antidepressant or benzodiazepine) is best used as an adjunct.

Chronic insomnia: outcome of hypnotherapeutic intervention in six cases.

Chronic dyssomnia is highly prevalent and has multiple etiologies. Hypnotherapy has been reported as beneficial for insomnia, but the description of the subject populations has been limited. A group of patients was evaluated at a sleep disorders center for a dyssomnia that occurred on at least 3 nights per week for 6 months or more. Six patients accepted hypnotherapy for their persistent psychophysiological insomnia and other sleep disorder diagnoses. Three patients responded to two sessions of structured hypnotherapy. The three responders remained improved at 16-month follow-up. Factors that seemed to contribute to long-term response in this small group of patients included a report of sleeping at least half of the time while in bed, increased hypnotic susceptibility, no history of major depression, and a lack of secondary gain.

Randomized, double-blind, placebo-controlled study of XP13512/GSK1838262 in patients with RLS.

OBJECTIVE: To assess the efficacy and tolerability of the nondopaminergic agent XP13512/GSK1838262 in adults with moderate to severe primary restless legs syndrome (RLS). METHODS: Patient Improvements in Vital Outcomes following Treatment in Restless Legs Syndrome I was a 12-week, multicenter, randomized, double-blind, placebo-controlled trial of XP13512 1,200 mg or placebo taken once daily at 5:00 pm with food. Coprimary endpoints were mean change from baseline International Restless Legs Scale (IRLS) total score and proportion of investigator-rated responders (very much improved or much improved on the Clinical Global Impression-Improvement scale) at week 12 (last observation carried forward). Tolerability was assessed using adverse events, vital signs, and clinical laboratory parameters. RESULTS: A total of 222 patients were randomized (XP13512 = 114, placebo = 108) and 192 patients (XP13512 = 100, placebo = 92) completed the study. At week 12, the mean change from baseline IRLS total score was greater with XP13512 (-13.2) compared with placebo (-8.8). Analysis of covariance, adjusted for baseline score and pooled site, demonstrated a mean treatment difference of -4.0 (95% confidence interval [CI], -6.2 to -1.9; p = 0.0003). More patients treated with XP13512 (76.1%) were responders compared with placebo (38.9%; adjusted OR 5.1; 95% CI, 2.8 to 9.2; p < 0.0001). Significant treatment effects for both coprimary measures were identified at week 1, the earliest time point measured. The most commonly reported adverse events were somnolence (XP13512 27%, placebo 7%) and dizziness (XP13512 20%, placebo 5%), which were mild to moderate in intensity and generally remitted. CONCLUSIONS: XP13512 1,200 mg, taken once daily, significantly improved restless legs syndrome (RLS) symptoms compared with placebo and was generally well tolerated in adults with moderate to severe primary RLS.

Validation of growth as measurand for bacterial adhesion to food and feed ingredients.

AIMS: A miniaturized adhesion test was designed to study the binding capacity of food and feed ingredients for bacterial cells. METHODS AND RESULTS: Bacteria were allowed to adhere to different fibrous materials supplied as well coatings in microtitration plates. The amount of bacteria retained on the materials was determined in an automated way as growth after addition of liquid medium. The test principle was based on an inverse relationship between initial cell densities and the appearance of growth: The higher adhering cell numbers are, the shorter are the detection times of growth. The growth curves obtained were fitted by nonlinear regression analysis employing a sigmoidal curve model. Growth parameters as (i) the time after incubation at which half of the maximum growth yield was reached; (ii) the time-coordinate of the point of inflection; (iii) the detection time calculated as x-axis intercept of the maximum specific growth rate in the point of inflection; and (iv) the time-coordinate of a growth detection threshold at OD = 0.05 were highly separating for the binding capacity of different food and feed ingredients for bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: With growth as measurand for adhesion, a simple, high-throughput method was developed for the screening of huge numbers of different binding matrices and bacteria.

Efficacy and safety of pramipexole in restless legs syndrome.

OBJECTIVE: To evaluate the efficacy and safety of pramipexole in patients with moderate to severe restless legs syndrome (RLS) METHODS: The authors conducted a 12-week, double-blind, randomized, placebo-controlled trial of fixed doses of pramipexole (0.25, 0.50, and 0.75 mg/day). Patients (N = 344) were up-titrated to their randomized dose over 3 weeks. The primary efficacy endpoints were patient ratings of symptom severity on the International RLS Study Group Rating Scale (IRLS) and clinician ratings of improvement on the Clinical Global Impressions-Improvement (CGI-I) scale. Secondary efficacy endpoints included visual analogue ratings of sleep and quality of life (QOL) RESULTS: By both primary measures, pramipexole was superior to placebo. For IRLS, the adjusted mean (SE) change from baseline to week 12 was -9.3 (1.0) for placebo, -12.8 (1.0) for 0.25 mg/day, -13.8 (1.0) for 0.50 mg/day, and -14.0 (1.0) for 0.75 mg/day (all p < 0.01). Similarly, pramipexole increased the percentage of patients with a CGI-I rating of "very much improved" or "much improved" at the end of the trial (51.2% for placebo and 74.7%, 67.9%, and 72.9% for pramipexole; all p < 0.05). Pramipexole significantly improved ratings of symptom severity, day and night, and also ratings of sleep satisfaction and QOL. Pramipexole was well tolerated: The most frequent adverse events with higher occurrence in the pramipexole group were nausea (19.0% vs 4.7%) and somnolence (10.1% vs 4.7%) CONCLUSION: As rated by patients and by clinicians, pramipexole was efficacious and safe in reducing the symptoms of restless legs syndrome.

Functional analysis of communities of aerobic heterotrophic bacteria from hydrocarbon-contaminated sites.

Microbial communities from soil and groundwater of oil-contaminated sites (Beelitzhof in Berlin-Nikolassee and the former Pintsch site in Hanau, both in Germany) were characterized by description of the physiological potential of arbitrary samples of 48 aerobic heterotrophic bacterial isolates. It was demonstrated that the sum of metabolic abilities, presented as a percentage of substrate-degrading microorganisms in a sample, is both site specific and reproducible. The percentage of hydrocarbon-degrading microorganisms in the communities was most strongly influenced by the diversity and amount of carbon supply (whereas after addition of mineral salts, total cell counts increased). For example, in groundwater of the waste oil-contaminated Pintsch site, only the accessible short-chain alkanes up to dodecane could be metabolized. After dosing with hydrogen peroxide, long-chain alkane-degrading bacteria were found in significant amounts among the predominant microorganisms, which was apparently due to a solubilization effect that brought the longer alkanes (and their degraders) into the groundwater. Because the addition of precultured organisms to a soil-composting windrow had no effect on the degradation pattern of its microbiota, the carbon sources available probably determined whether allochthonous bacteria would become indigenous. Although the physiological potentials of the individual bacteria complemented each other and thus determined the distinctive profile characteristic of the microbial community, the individual members could differ in their metabolic abilities, as was shown by the distribution of positive test results in different samples, and they could also differ in their taxonomic status. Evidently, the taxonomic status of the bacteria did not determine their activities: Strains of the same species showed different degradation abilities for hydrocarbon substrates. However, the taxonomic status of isolates seemed to be highly dependent on the physicochemical factors of a site (soil structure, water capacity, etc.).