Periacetabular osteotomy restores the typically excessive range of motion in dysplastic hips with a spherical head

BACKGROUND Residual acetabular dysplasia is seen in combination with femoral pathomorphologies including an aspherical femoral head and valgus neck-shaft angle with high antetorsion. It is unclear how these femoral pathomorphologies affect range of motion (ROM) and impingement zones after periacetabular osteotomy. QUESTIONS/PURPOSES (1) Does periacetabular osteotomy (PAO) restore the typically excessive ROM in dysplastic hips compared with normal hips; (2) how do impingement locations differ in dysplastic hips before and after PAO compared with normal hips; (3) does a concomitant cam-type morphology adversely affect internal rotation; and (4) does a concomitant varus-derotation intertrochanteric osteotomy (IO) affect external rotation? METHODS Between January 1999 and March 2002, we performed 200 PAOs for dysplasia; of those, 27 hips (14%) met prespecified study inclusion criteria, including availability of a pre- and postoperative CT scan that included the hip and the distal femur. In general, we obtained those scans to evaluate the pre- and postoperative acetabular and femoral morphology, the degree of acetabular reorientation, and healing of the osteotomies. Three-dimensional surface models based on CT scans of 27 hips before and after PAO and 19 normal hips were created. Normal hips were obtained from a population of CT-based computer-assisted THAs using the contralateral hip after exclusion of symptomatic hips or hips with abnormal radiographic anatomy. Using validated and computerized methods, we then determined ROM (flexion/extension, internal- [IR]/external rotation [ER], adduction/abduction) and two motion patterns including the anterior (IR in flexion) and posterior (ER in extension) impingement tests. The computed impingement locations were assigned to anatomical locations of the pelvis and the femur. ROM was calculated separately for hips with (n = 13) and without (n = 14) a cam-type morphology and PAOs with (n = 9) and without (n = 18) a concomitant IO. A post hoc power analysis based on the primary research question with an alpha of 0.05 and a beta error of 0.20 revealed a minimal detectable difference of 4.6° of flexion. RESULTS After PAO, flexion, IR, and adduction/abduction did not differ from the nondysplastic control hips with the numbers available (p ranging from 0.061 to 0.867). Extension was decreased (19° ± 15°; range, -18° to 30° versus 28° ± 3°; range, 19°-30°; p = 0.017) and ER in 0° flexion was increased (25° ± 18°; range, -10° to 41° versus 38° ± 7°; range, 17°-41°; p = 0.002). Dysplastic hips had a higher prevalence of extraarticular impingement at the anteroinferior iliac spine compared with normal hips (48% [13 of 27 hips] versus 5% [one of 19 hips], p = 0.002). A PAO increased the prevalence of impingement for the femoral head from 30% (eight of 27 hips) preoperatively to 59% (16 of 27 hips) postoperatively (p = 0.027). IR in flexion was decreased in hips with a cam-type deformity compared with those with a spherical femoral head (p values from 0.002 to 0.047 for 95°-120° of flexion). A concomitant IO led to a normalization of ER in extension (eg, 37° ± 7° [range, 21°-41°] of ER in 0° of flexion in hips with concomitant IO compared with 38° ± 7° [range, 17°-41°] in nondysplastic control hips; p = 0.777). CONCLUSIONS Using computer simulation of hip ROM, we could show that the PAO has the potential to restore the typically excessive ROM in dysplastic hips. However, a PAO can increase the prevalence of secondary intraarticular impingement of the aspherical femoral head and extraarticular impingement of the anteroinferior iliac spines in flexion and internal rotation. A cam-type morphology can result in anterior impingement with restriction of IR. Additionally, a valgus hip with high antetorsion can result in posterior impingement with decreased ER in extension, which can be normalized with a varus derotation IO of the femur. However, indication of an additional IO needs to be weighed against its inherent morbidity and possible complications. The results are based on a limited number of hips with a pre- and postoperative CT scan after PAO. Future prospective studies are needed to verify the current results based on computer simulation and to test their clinical importance.

Prognostic value of PCSK9 levels in patients with acute coronary syndromes.

AIMS Proprotein convertase subtilisin kexin 9 (PCSK9) is an emerging target for the treatment of hypercholesterolaemia, but the clinical utility of PCSK9 levels to guide treatment is unknown. We aimed to prospectively assess the prognostic value of plasma PCSK9 levels in patients with acute coronary syndromes (ACS). METHODS AND RESULTS Plasma PCSK9 levels were measured in 2030 ACS patients undergoing coronary angiography in a Swiss prospective cohort. At 1 year, the association between PCSK9 tertiles and all-cause death was assessed adjusting for the Global Registry of Acute Coronary Events (GRACE) variables, as well as the achievement of LDL cholesterol targets of <1.8 mmol/L. Patients with higher PCSK9 levels at angiography were more likely to have clinical familial hypercholesterolaemia (rate ratio, RR 1.21, 95% confidence interval, CI 1.09-1.53), be treated with lipid-lowering therapy (RR 1.46, 95% CI 1.30-1.63), present with longer time interval of chest pain (RR 1.29, 95% CI 1.09-1.53) and higher C-reactive protein levels (RR 1.22, 95% CI 1.16-1.30). PCSK9 increased 12-24 h after ACS (374 ± 149 vs. 323 ± 134 ng/mL, P < 0.001). At 1 year follow-up, HRs for upper vs. lower PCSK9-level tertiles were 1.13 (95% CI 0.69-1.85) for all-cause death and remained similar after adjustment for the GRACE score. Patients with higher PCSK9 levels were less likely to reach the recommended LDL cholesterol targets (RR 0.81, 95% CI 0.66-0.99). CONCLUSION In ACS patients, high initial PCSK9 plasma levels were associated with inflammation in the acute phase and hypercholesterolaemia, but did not predict mortality at 1 year.

Characterization of the Axial Jet Separator with a CO2/Helium Mixture: Toward GC-AMS Hyphenation

Development of interfaces for sample introduction from high pressures is important for real-time online hyphenation of chromatographic and other separation devices with mass spectrometry (MS) or accelerator mass spectrometry (AMS). Momentum separators can reduce unwanted low-density gases and introduce the analyte into the vacuum. In this work, the axial jet separator, a new momentum interface, is characterized by theory and empirical optimization. The mathematical model describes the different axial penetration of the components of a jetgas mixture and explains the empirical results for injections of CO2 in helium into MS and AMS instruments. We show that the performance of the new interface is sensitive to the nozzle size, showing good qualitative agreement with the mathematical model. Smaller nozzle sizes are more preferable due to their higher inflow capacity. The CO2 transmission efficiency of the interface into a MS instrument is ~14% (CO2/helium separation factor of 2.7). The interface receives and delivers flows of ~17.5 mL/min and ~0.9 mL/min, respectively. For the interfaced AMS instrument, the ionization and overall efficiencies are 0.7-3% and 0.1-0.4%, respectively, for CO2 amounts of 4-0.6 µg C, which is only slightly lower compared to conventional systems using intermediate trapping. The ionization efficiency depends on to the carbon mass flow in the injected pulse and is suppressed at high CO2 flows. Relative to a conventional jet separator, the transmission efficiency of the axial jet separator is lower, but its performance is less sensitive to misalignments.

Long-term evaluation of Class II subdivision treatment with unilateral maxillary first molar extraction

OBJECTIVE To evaluate the long-term effects of asymmetrical maxillary first molar (M1) extraction in Class II subdivision treatment. MATERIALS AND METHODS Records of 20 Class II subdivision whites (7 boys, 13 girls; mean age, 13.0 years; SD, 1.7 years) consecutively treated with the Begg technique and M1 extraction, and 15 untreated asymmetrical Class II adolescents (4 boys, 11 girls; mean age, 12.2 years; SD, 1.3 years) were examined in this study. Cephalometric analysis and PAR assessment were carried out before treatment (T1), after treatment (T2), and on average 2.5 years posttreatment (T3) for the treatment group, and at similar time points and average follow-up of 1.8 years for the controls. RESULTS The adjusted analysis indicated that the maxillary incisors were 2.3 mm more retracted in relation to A-Pog between T1 and T3 (β  =  2.31; 95% CI; 0.76, 3.87), whereas the mandibular incisors were 1.3 mm more protracted (β  =  1.34; 95% CI; 0.09, 2.59), and 5.9° more proclined to the mandibular plane (β  =  5.92; 95% CI; 1.43, 10.41) compared with controls. The lower lip appeared 1.4 mm more protrusive relative to the subnasale-soft tissue-Pog line throughout the observation period in the treated adolescents (β  =  1.43; 95% CI; 0.18, 2.67). There was a significant PAR score reduction over the entire follow-up period in the molar extraction group (β  =  -6.73; 95% CI; -10.7, -2.7). At T2, 65% of the subjects had maxillary midlines perfectly aligned with the face. CONCLUSIONS Unilateral M1 extraction in asymmetrical Class II cases may lead to favorable occlusal outcomes in the long term without harming the midline esthetics and soft tissue profile.

Reconstruction of Chronic Foveal TFCC Tears with an Autologous Tendon Graft

Background A triangular fibrocartilage complex (TFCC) injury can produce distal radioulnar joint (DRUJ) instability. If the foveal attachment is avulsed, it translates distally. The footprint is separated from its origin and will become covered in synovitis, preventing healing. The authors describe a surgical technique for the treatment of instability of the DRUJ due to chronic foveal detachment of the TFCC. Technique The procedure utilizes a loop of autologous palmaris longus tendon graft passed through the ulnar aspect of the TFCC and through an osseous tunnel in the distal ulna to reconstruct the fovel attachment. Patients and Methods We report on nine patients with a mean age of 42. Median follow-up was 13 months. Results The median pain scores measured were reduced from 8 to 3 postoperatively, and all had a stable DRUJ. Conclusions This technique provides stability of the distal ulna to the radius and carpus, with potential for biologic healing through osseous integration. It is a robust, anatomically based reconstruction of the TFCC to the fovea that stabilizes the DRUJ and the ulnar-carpal sag.

Comparison between magnetic resonance imaging and computed tomography of the lung in patients with cystic fibrosis with regard to clinical, laboratory, and pulmonary functional parameters

OBJECTIVE To evaluate whether magnetic resonance imaging (MRI) is effective as computed tomography (CT) in determining morphologic and functional pulmonary changes in patients with cystic fibrosis (CF) in association with multiple clinical parameters. MATERIALS AND METHODS Institutional review board approval and patient written informed consent were obtained. In this prospective study, 30 patients with CF (17 men and 13 women; mean (SD) age, 30.2 (9.2) years; range, 19-52 years) were included. Chest CT was acquired by unenhanced low-dose technique for clinical purposes. Lung MRI (1.5 T) comprised T2- and T1-weighted sequences before and after the application of 0.1-mmol·kg gadobutrol, also considering lung perfusion imaging. All CT and MR images were visually evaluated by using 2 different scoring systems: the modified Helbich and the Eichinger scores. Signal intensity of the peribronchial walls and detected mucus on T2-weighted images as well as signal enhancement of the peribronchial walls on contrast-enhanced T1-weighted sequences were additionally assessed on MRI. For the clinical evaluation, the pulmonary exacerbation rate, laboratory, and pulmonary functional parameters were determined. RESULTS The overall modified Helbich CT score had a mean (SD) of 15.3 (4.8) (range, 3-21) and median of 16.0 (interquartile range [IQR], 6.3). The overall modified Helbich MR score showed slightly, not significantly, lower values (Wilcoxon rank sum test and Student t test; P > 0.05): mean (SD) of 14.3 (4.7) (range, 3-20) and median of 15.0 (IQR, 7.3). Without assessment of perfusion, the overall Eichinger score resulted in the following values for CT vs MR examinations: mean (SD), 20.3 (7.2) (range, 4-31); and median, 21.0 (IQR, 9.5) vs mean (SD), 19.5 (7.1) (range, 4-33); and median, 20.0 (IQR, 9.0). All differences between CT and MR examinations were not significant (Wilcoxon rank sum tests and Student t tests; P > 0.05). In general, the correlations of the CT scores (overall and different imaging parameters) to the clinical parameters were slightly higher compared to the MRI scores. However, if all additional MRI parameters were integrated into the scoring systems, the correlations reached the values of the CT scores. The overall image quality was significantly higher for the CT examinations compared to the MRI sequences. CONCLUSIONS One major diagnostic benefit of lung MRI in CF is the possible acquisition of several different morphologic and functional imaging features without the use of any radiation exposure. Lung MRI shows reliable associations with CT and clinical parameters, which suggests its implementation in CF for routine diagnosis, which would be particularly important in follow-up imaging over the long term.

Prospective analysis of adrenal function in patients with acute exacerbations of COPD: the Reduction in the Use of Corticosteroids in Exacerbated COPD (REDUCE) trial

OBJECTIVE To analyze prospectively the hypothalamic-pituitary-adrenal (HPA) axis and clinical outcome in patients treated with prednisone for exacerbated chronic obstructive pulmonary disease (COPD). DESIGN Prospective observational study. SUBJECTS AND METHODS Patients presenting to the emergency department were randomized to receive 40 mg prednisone daily for 5 or 14 days in a placebo-controlled manner. The HPA axis was longitudinally assessed with the 1 μg corticotropin test and a clinical hypocortisolism score at baseline, on day 6 before blinded treatment, at hospital discharge, and for up to 180 days of follow-up. Prednisone was stopped abruptly, irrespective of the test results. Patients discharged with pathological test results received instructions about emergency hydrocortisone treatment. RESULTS A total of 311 patients were included in the analysis. Mean basal and stimulated serum total cortisol levels were highest on admission (496±398 and 816±413 nmol/l respectively) and lowest on day 6 (235±174 and 453±178 nmol/l respectively). Pathological stimulation tests were found in 63, 38, 9, 3, and 2% of patients on day 6, at discharge, and on days 30, 90, and 180 respectively, without significant difference between treatment groups. Clinical indicators of hypocortisolism did not correlate with stimulation test results, but cortisol levels were inversely associated with re-exacerbation risk. There were no hospitalizations or deaths as a result of adrenal crisis. CONCLUSION Dynamic changes in the HPA axis occur during and after the treatment of acute exacerbations of COPD. In hypocortisolemic patients who were provided with instructions about stress prophylaxis, the abrupt termination of prednisone appeared safe.

The role of vulnerability factors in individuals with an at-risk mental state of psychosis

Background Several indicators of heightened vulnerability to psychosis and relevant stressors have been identified. However, it has rarely been studied prospectively to what extent these vulnerability factors are in fact more frequently present in individuals with an at-risk mental state for psychosis. Moreover, it remains unknown whether any of these contribute to the prediction of psychosis onset in at-risk mental state individuals. Methods There were 28 healthy controls, 86 first-episode psychosis patients and 127 at-risk mental state individuals recruited within the Basel “Früherkennung von Psychosen” project. Relative frequencies of selected vulnerability factors for psychosis were compared between healthy controls, psychosis patients, those at-risk mental state individuals with subsequent psychosis onset (n = 31) and those without subsequent psychosis onset (n = 55). Survival analyses were applied to determine associations between time to transition to psychosis and vulnerability factors in all 127 at-risk mental state individuals. Results The vulnerability factors/indicators such as “difficulties during school education or vocational training”, “difficulties during employment”, “being single”, “difficulties with intimate relationships” and “being burdened with specific stressful situations” were more commonly found in the at-risk mental state and first-episode psychosis group than in healthy controls. Conclusions At-risk mental state and first-episode psychosis individuals more frequently present with vulnerability factors. Individual vulnerability factors appear, however, not to be predictive for an onset of psychosis.

DNA-DAMAGING REACTIONS OF NEOCARZINOSTATIN (ANTIBIOTICS, DNA REPAIR, CYTOTOXICITY)

Sensitive assays utilizing a cell-free and an intracellular system were employed to study the molecular bases of the DNA-damaging reactions of neocarzinostatin (NCS). In the cell-free DNA system, super-helical form I DNA from the bacteriophage PM2 was used as the substrate. The three forms of DNA present after treatment with NCS were separated by agarose gel electrophoresis. When NCS-damaged DNA was assayed under neutral conditions, there was a progressive decrease in the amount of surviving form I DNA and a corresponding increase in form II (nicked, relaxed circular) DNA, but very little increase in form III (linear duplex) DNA. This indicates that NCS introduces primarily single-strand breaks. However later studies showed that there were some site-specific double-strand breaks mediated by NCS on PM2 DNA. Seven such specific sites were mapped on the PM2 genome. When the damage was assayed under nondenaturing alkaline conditions or with the apurinic/apyrimidinic endonuclease IV, there was a slightly greater decrease in the amount of surviving form I DNA compared with neutral conditions indicating the presence of some alkali-labile sites.^ NCS-mediated DNA damage and repair were examined with cultured Chinese hamster ovary (CHO) cells using either alkaline elution for analysis of single-strand breaks or neutral elution for analysis of double-strand breaks. Most of the strand breaks introduced by NCS were capable of being rejoined. However, there was a small amount of residual DNA damage remaining unrejoined at 24-hr after removal of the drug. The amount of residual DNA damage was higher in a CHO mutant cell line (EM9) having a higher sensitivity to killing by NCS than its parental strain (AA8). Other lesions, DNA-protein complexes and alkali-labile sites, were detected after NCS treatment but they constituted only a small fraction of the DNA damage.^ Based on the above information, it can be postulated that NCS introduces some very lethal DNA damage. It is likely that the lethal lesions are a subset of the total DNA lesions representing the residual DNA damage. This DNA damage may be composed of site-specific, unrejoinable double-strand breaks and are thus the primary lesion leading to NCS-mediated lethality.^

Age Related Differences in Individual Quality of Life Domains in Youth with Type 1 Diabetes.

BACKGROUND: Investigating individual, as opposed to predetermined, quality of life domains may yield important information about quality of life. This study investigated the individual quality of life domains nominated by youth with type 1 diabetes. METHODS: Eighty young people attending a diabetes summer camp completed the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting interview, which allows respondents to nominate and evaluate their own quality of life domains. RESULTS: The most frequently nominated life domains were 'family', 'friends', 'diabetes', 'school', and 'health' respectively; ranked in terms of importance, domains were 'religion', 'family', 'diabetes', 'health', and 'the golden rule'; ranked in order of satisfaction, domains were 'camp', 'religion', 'pets', and 'family' and 'a special person' were tied for fifth. Respondent age was significantly positively associated with the importance of 'friends', and a significantly negatively associated with the importance of 'family'. Nearly all respondents nominated a quality of life domain relating to physical status, however, the specific physical status domain and the rationale for its nomination varied. Some respondents nominated 'diabetes' as a domain and emphasized diabetes 'self-care behaviors' in order to avoid negative health consequences such as hospitalization. Other respondents nominated 'health' and focused more generally on 'living well with diabetes'. In an ANOVA with physical status domain as the independent variable and age as the dependent variable, participants who nominated 'diabetes' were younger (M = 12.9 years) than those who nominated 'health' (M = 15.9 years). In a second ANOVA, with rationale for nomination the physical status domain as the independent variable, and age as the dependent variable, those who emphasized 'self care behaviors' were younger (M = 11.8 years) than those who emphasized 'living well with diabetes' (M = 14.6 years). These differences are discussed in terms of cognitive development and in relation to the decline in self-care and glycemic control often observed during adolescence. CONCLUSIONS: Respondents nominated many non-diabetes life domains, underscoring that QOL is multidimensional. Subtle changes in conceptualization of diabetes and health with increasing age may reflect cognitive development or disease adjustment, and speak to the need for special attention to adolescents. Understanding individual quality of life domains can help clinicians motivate their young patients with diabetes for self-care. Future research should employ a larger, more diverse sample, and use longitudinal designs.

The association of HSV 1 and 2 with atherosclerosis defined by CRP level

A study of the association of Herpes simplex virus 1 and 2 exposure to early atherosclerosis using high C-reactive protein level as a marker was carried out in US born, non-pregnant, 20-49 year olds participating in a national survey between 1999 and 2004. Participants were required to have valid results for Herpes simplex virus 1 and 2 and C-Reactive Protein for inclusion. Cases were those found to have a high C-reactive protein level of 0.3-1 mg/dL, while controls had low to normal values (0.01-0.29 mg/dL). Overall, there were 1211 cases and 2870 controls. Mexican American and non-Hispanic black women were much more likely to fall into the high cardiac risk group than the other sex race groups with proportions of 44% and 39%, respectively. ^ Herpesvirus exposure was categorized such that Herpes simplex virus 1 and 2 exposure could be studied simultaneously within the same individual and models. The HSV 1+, HSV 2- category included the highest percentage (45.63%) of participants, followed by HSV 1-, HSV 2- (30.16%); HSV 1+, HSV 2+ (15.09%); and HSV 1-, HSV 2+ (9.12%) respectively. The proportion of participants in the HSV 1+, HSV 2- category was substantially higher in Mexican Americans (63%-66%). Further, the proportion in the HSV 1+, HSV 2+ category was notably higher in the non-Hispanic black participants (23%-44%). Non-Hispanic black women also had the highest percentage of HSV 1-, HSV 2+ exposure of all the sex race groups at 17%. ^ Overall, the unadjusted odds ratios for atherosclerotic disease defined by C-reactive protein with HSV 1-, HSV 2- as the referent group was 1.62 (95% CI 1.23-2.14) for HSV 1 +, HSV 2+; 1.3 (95% CI 1.10-1.69 for HSV 1+, HSV 2-; and 1.52 (95% CI 1.14-2.01). When the study was stratified into sex-race groups, only HSV 1+, HSV 2- in the Non-Hispanic white men remained significant (OR=1.6; 95% CI 1.06-2.43). Adjustment for selected covariates was made in the multivariate model for both the overall and sex-race stratified studies. High C-reactive protein values were not associated with any of the Herpesvirus exposure levels in either the overall or stratified analyses. ^

The incidence of necrotizing changes in adults with pneumococcal pneumonia

Background. Necrotizing pneumonia is generally considered a rare complication of pneumococcal pneumonia in adults. We systematically studied the incidence of necrotizing changes in adult patients with pneumococcal pneumonia, and examined the severity of infection, the role of causative serotype and the association with bacteremia. ^ Methods. We used a data base of all pneumococcal infections identified at our medical center between 2000 and 2010. Original readings of chest X-rays (CXR) and computerized tomography (CT) were noted. All images were then reread independently by 2 radiologists. The severity of disease was assessed using the SMART-COP scoring system. ^ Results. There were 351 cases of pneumococcal pneumonia. Necrosis was reported in no original CXR readings and 6 of 136 (4.4%) CTs. With re-reading, 8 of 351 (2.3%) CXR and 15 of 136 (11.0%) CT had necrotizing changes. Overall, these changes were found in 23 of 351 (6.6%, 95% CI 4.0 - 9.1) patients. The incidence of bacteremia and the admitting SMART-COP scores were similar in patients with and without necrosis (P=1.00 and P=0.32, respectively). Type 3 pneumococcus was more commonly isolated from patients with than from patients without necrotizing pneumonia (P=0.05), but a total of 10 serotypes were identified among 16 cases in which the organism was available for typing. ^ Conclusions. Necrotizing changes in the lungs were seen in 6.6% (95% CI 4.0 - 9.1) of a large series of adults with pneumococcal pneumonia. Patients with necrosis were not more likely to have bacteremia or more severe disease. Type 3 pneumococcus was commonly implicated, but 9 other serotypes were also identified.^

The distribution of sulfur in oceanic crust with respect to oxidative diagenesis (Table 1)

A detailed geochemical-petrological examination of layer 2 basalts recovered during Leg 37 of the DSDP has revealed that the original distribution, form and abundance of igneous sulfide have been profoundly altered during low-grade oxidative diagenesis. The net result appears to have been a rather pervasive remobilization of igneous sulfide to form secondary pyrite accompanied by a bulk loss of sulfur equivalent to about 50-60% of the original igneous value, assuming initial saturation. It is suggested that during infiltration of seawater into the massive crystalline rock, igneous sulfide has experienced pervasive oxidation, under conditions of limited oxidation potential, to form a series of unstable, soluble sulfur species, primarily in the form of SO3[2-] and S2O3[2-]. Spontaneous decomposition of these intermediate compounds through disproportionation has resulted in partial reconstitution of the sulfur as secondary pyrite and the generation of SO4[2-] ion, which, due to its kinetic stability, has been lost from the basalt system and ultimately transferred to the ocean. This model not only satisfies the geochemical and petrological observations but also provides a suitable explanation for the highly variable delta34S values which characterize secondary sulfides in deep ocean floor basalts.

Mats of psychrophilic thiotrophic bacteria associated with cold seeps of the Barents Sea

This study focused on the bacterial diversity associated with microbial mats of deep-sea cold seeps at the Norwegian continental margin. Study sites included the Storegga and Nyegga areas as well as the Håkon Mosby mud volcano, where the mats occurred at temperatures permanently close to the freezing point of seawater. Two visually different mat types, i.e. small gray mats and extensive white mats, were studied with the aim to determine the identity of the mat-forming sulfide oxidizers, and to investigate which environmental factors (e.g. sulfate reduction and methane oxidation rates) shown here could explain the observed diversity. Sequence data have been submitted to the EMBL database under accession No. FR847864-FR847887 (giant sulfur bacteria), No. FR827864 (Menez Gwen filament; see Supplementary Material) and No. FR875365-FR877509 (except FR875905; remaining partial sequences).