Repeat epidural steroid injections for radicular pain due to lumbar or cervical disc herniation: what happens after 'salvage treatment'?.

AIMS: The aim of this study was to determine the efficacy of repeat epidural steroid injections as a form of treatment for patients with insufficiently controlled or recurrent radicular pain due to a lumbar or cervical disc herniation. PATIENTS AND METHODS: A cohort of 102 patients was prospectively followed, after an epidural steroid injection for radicular symptoms due to lumbar disc herniation, in 57 patients, and cervical disc herniation, in 45 patients. Those patients with persistent pain who requested a second injection were prospectively followed for one year. Radicular and local pain were assessed on a visual analogue scale (VAS), functional outcome with the Oswestry Disability Index (ODI) or the Neck Pain and Disability Index (NPAD), as well as health-related quality of life (HRQoL) using the 12-Item Short-Form Health Survey questionnaire (SF-12). RESULTS: A second injection was performed in 17 patients (29.8%) with lumbar herniation and seven (15.6%) with cervical herniation at a mean of 65.3 days (sd 46.5) and 47 days (sd 37.2), respectively, after the initial injection. All but one patient, who underwent lumbar microdiscectomy, responded satisfactorily with a mean VAS for leg pain of 8.8 mm (sd 10.3) and a mean VAS for arm pain of 6.3 mm (sd 9) one year after the second injection, respectively. Similarly, functional outcome and HRQoL were improved significantly from the baseline scores: mean ODI, 12.3 (sd 12.4; p < 0.001); mean NPAD, 19.3 (sd 24.3; p = 0.041); mean SF-12 physical component summary (PCS) in lumbar herniation, 46.8 (sd 7.7; p < 0.001); mean SF-12 PCS in cervical herniation, 43 (sd 6.8; p = 0.103). CONCLUSION: Repeat steroid injections are a justifiable form of treatment in symptomatic patients with lumbar or cervical disc herniation whose symptoms are not satisfactorily relieved after the first injection. Cite this article: Bone Joint J 2018;100-B:1364-71.

Stimulated two-photon emission in bulk CdSe.

While two-photon emission processes are firmly established in atomic physics, their observation and use in semiconductor physics remains elusive. Here, we experimentally investigate stimulated two-photon emission in photoexcited bulk CdSe and identify requirements for the observation of stimulated two-photon emission. In particular, this process requires population inversion as well as two-photon transition energies close to the bandgap energy. In any regime investigated in the present study, net optical gain is not achieved, as the free-carrier absorption intrinsically linked to the photoexcitation completely masks the two-photon gain. The results are well in line with a recent study on nondegenerate versions of two-photon emission in GaAs and place clear limits for the practical use of two-photon emission in optically excited semiconductors.

Electrical control of interdot electron tunneling in a double InGaAs quantum-dot nanostructure.

We employ ultrafast pump-probe spectroscopy to directly monitor electron tunneling between discrete orbital states in a pair of spatially separated quantum dots. Immediately after excitation, several peaks are observed in the pump-probe spectrum due to Coulomb interactions between the photogenerated charge carriers. By tuning the relative energy of the orbital states in the two dots and monitoring the temporal evolution of the pump-probe spectra the electron and hole tunneling times are separately measured and resonant tunneling between the two dots is shown to be mediated both by elastic and inelastic processes. Ultrafast (<5 ps) interdot tunneling is shown to occur over a surprisingly wide bandwidth, up to ∼8 meV, reflecting the spectrum of exciton-acoustic phonon coupling in the system.

Quantum interference control of femtosecond, microA current bursts in single GaAs nanowires.

A phase-stable superposition of femtosecond pulses from a compact erbium-doped fiber source and their second harmonic is shown to induce ultrashort approximately microA current bursts in single unbiased GaAs nanowires. Current injection relies on a quantum interference of one- and two-photon absorption pathways. The vector direction of the current is solely dictated by the polarization and relative phase of the harmonically related light components while its power dependence is consistent with a third order optical nonlinearity.

Role of coagulation and fibrinolysis in lung and renal fibrosis.

Elevated procoagulant and suppressed fibrinolytic activities are regularly encountered in different forms of clinical and experimental fibrosis of the lungs and the kidneys. Although primarily serving to provide a provisional matrix of repair largely consisting of fibrin and fibronectin, the involved procoagulant serine proteases and protease inhibitors may also exert distinct cellular downstream signaling events modifying the fibrotic response. In this review, evidence for an impaired regulation of coagulation and fibrinolysis factors in clinical and experimental lung and renal fibrosis is provided and the role of PAR (protease activated receptor) induced profibrotic and HGF (hepatocyte growth factor) elicited antifibrotic cellular events is worked out. In view of experiments obtained in animal models of lung and renal fibrosis, the potential therapeutic usefulness of anticoagulant or profibrinolytic strategies is discussed.

Keratinocyte growth factor prevents intra-alveolar oedema in experimental lung isografts.

Primary graft dysfunction, characterised by intra-alveolar oedema, is a major obstacle in pulmonary transplantation. The present study evaluates the potential of keratinocyte growth factor (palmiferin; DeltaN23-KGF) for the prevention of oedema in lung transplants. Intratracheal instillation of 5 mg x kg(-1) DeltaN23-KGF was performed in Lewis rats on days 3 and 2 before explantation. Control animals obtained an equivalent volume of vehicle. Left lungs were isogeneically transplanted and the graft recipients were sacrificed 1 day later for stereological analysis of intra-alveolar oedema and bronchoalveolar lavage. The total protein and phospholipid content, as well as surfactant proteins, were measured. Surfactant activity was analysed with a pulsating bubble surfactometer. In grafts from control treated donors, the fraction of intra-alveolar oedema amounted to 3.4+/-1.1% of the total parenchymal volume. Treatment of donor lungs with DeltaN23-KGF reduced oedema to a fraction of 1.6+/-0.8%. In the lavage fluid of pulmonary grafts from DeltaN23-KGF-treated donors, the total protein content was decreased compared with vehicle-treated lung transplants, whereas phospholipids did not differ. The protein fraction contained increased amounts of surfactant protein-C after DeltaN23-KGF treatment and surfactant function was improved. Treatment of donor lungs with palifermin protects against intra-alveolar oedema formation upon transplantation. This effect appears to be mediated by an improved surfactant homeostasis.

Cellular origin of pro-coagulant and (anti)-fibrinolytic factors in bleomycin-injured lungs.

Excessive pro-coagulant and decreased fibrinolytic activities in the alveolar compartment have been repeatedly documented for inflammatory and fibrotic lung diseases. The current authors determined the contribution of different resident lung cells to the altered local production of coagulation- and fibrinolysis-system components in bleomycin-injured mouse lungs via cell-specific and quantitative assessment of mRNA levels of various pro-coagulant and (anti)-fibrinolytic factors. Laser-assisted microdissection technology was used to sample specific cell populations in combination with subsequent mRNA analysis by real-time quantitative reverse transcriptase-PCR. Additionally, western blot analysis, immunohistochemistry and activity assays were performed. Following bleomycin challenge, the strongest induction of tissue factor and plasminogen activator inhibitor (PAI)-1 mRNA expression was observed in alveolar macrophages (approximately 250- and 60-fold induction, respectively). These factors were also upregulated in alveolar type II cells, but to an approximately six-fold lesser extent. In contrast, PAI-2 expression was induced exclusively in alveolar macrophages. A slight increase of urokinase-type plasminogen activator (uPA) expression was also observed in alveolar macrophages (two-fold induction), but uPA activity was reduced due to a disproportionate increase of PAI production. Alveolar macrophages and, to a lesser extent, alveolar type II cells are the main sources of locally produced pro-coagulant and anti-fibrinolytic factors in bleomycin-injured lungs.

Surfactant protein C mutations in sporadic forms of idiopathic interstitial pneumonias.

Interstitial pneumonias have recently been associated with mutations in the gene encoding surfactant protein C (SFTPC). In particular, SFTPC mutations have been reported in a number of familial forms of pulmonary fibrosis and in infants with interstitial lung diseases. The present study searched for SFTPC mutations in adult patients with sporadic idiopathic interstitial pneumonia. In total, 35 adult patients with sporadic idiopathic interstitial pneumonia and 50 healthy subjects were investigated for SFTPC mutations by direct DNA sequencing. Of the patients with sporadic idiopathic interstitial pneumonia, 25 suffered from idiopathic pulmonary fibrosis and 10 patients from nonspecific interstitial pneumonia. Only two frequent nonsynonymous variants, T138N and S186N, were detected. Allele frequencies of both variations as well as of other identified noncoding alterations did not differ significantly between the diverse patient groups and control subjects. In conclusion, mutations in the gene encoding surfactant protein C are not common in sporadic cases of idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia, suggesting that the mutated gene does not play an important role in the pathogenesis of these forms of idiopathic interstitial pneumonia.

Alveolar antioxidant status in patients with acute respiratory distress syndrome.

In the acutely inflamed lung, oxidant stress occurs within the alveolar compartment. Under these conditions, the regulation of low molecular weight antioxidants in the epithelial lining fluid is poorly understood. Therefore, antioxidant levels were measured in the bronchoalveolar lavage fluid (BALF) of patients with acute respiratory distress syndrome (ARDS; n=40) and in healthy volunteers (n=20). Reduced glutathione (GSH), oxidised glutathione (GSSG; enzymatic assay), retinol (vitamin A), alpha-tocopherol (vitamin E), ascorbic acid (vitamin C), uric acid (all by HPLC), plasmalogens (1-alkenyl-2-acyl phospholipids), polyunsaturated fatty acids (PUFA; both by gas-liquid chromatography), and F2-isoprostanes (ELISA) were quantified. All values are expressed as concentrations in cell-depleted BALF. GSSG (ARDS: 0.13+/-0.02 microM; control: 0.03+/-0.01 microM; mean+/-sem) and F2-isoprostanes (ARDS: 78+/-10 pM; control: 26+/-5 pM) were increased in ARDS, thus indicating oxidant stress. GSH levels in patients did not change significantly, whereas concentrations of vitamins A and C, vitamin E (ARDS: 77+/-15 nM; control: 26+/-3 nM) and uric acid (ARDS: 11.8+/-2.2 microM; control: 0.7+/-0.0 microM) were significantly elevated in ARDS. PUFA of total lipids, which may act as sacrificial antioxidants, increased by a factor of approximately 3 in patients, but plasmalogens showed a significant decrease. In conclusion, low molecular weight antioxidants are elevated in the alveolar compartment of patients with acute respiratory distress syndrome. Further research is warranted to elucidate the molecular mechanisms underlying this finding.

Bronchoscopic administration of bovine natural surfactant in ARDS and septic shock: impact on biophysical and biochemical surfactant properties.

The purpose of the present study was to investigate the impact of bronchoscopic surfactant administration, on the biochemical and biophysical surfactant properties, in patients with severe and early acute respiratory distress syndrome (ARDS) and septic shock. A total number of 27 ARDS patients received 300-500 mg x kg x body x weight(-1) of a natural bovine surfactant extract (Alveofact) via a flexible bronchoscope. Bronchoalveolar lavages were performed 3 h prior to, and 15-18 h and 72 h after surfactant administration. A comparison to healthy volunteers, undergoing an identical lavage procedure, was made (control, n=12). Severe biophysical and biochemical surfactant abnormalities were encountered throughout in the ARDS patients. These included a massive alveolar protein load, a reduced percentage of large surfactant aggregates (LA), a loss of palmitoylated phosphatidylcholine species and a significant reduction of surfactant apoprotein (SP)-A, SP-B and SP-C in the LA fraction. Both minimum (gammamin) and adsorption (gammaads) surface tension values (pulsating bubble surfactometer) were dramatically increased. Surfactant treatment resulted in a marked increase in the lavagable phospholipid (PL) pool, but predominance of the alveolar surfactant-inhibitory protein load was still encountered. Far-reaching or even complete normalization of the PL profile, the LA fraction and its SP-B and SP-C (but not SP-A) content as well as the fatty acid composition of the phosphatidylcholine class was noted. Surface tension lowering properties (gammamin and gammaads) significantly improved, but were still not fully normalized. Bronchoscopic administration of large quantities of natural bovine surfactant in severe acute respiratory distress syndrome causes far-reaching restoration of biochemical surfactant properties and significant improvement, however not full normalization, of biophysical surfactant function.

Canine dysautonomia: two clinical cases.

Two clinical cases of canine dysautonomia are described. Two young female neutered dogs were presented with clinical signs including vomiting, diarrhoea, faecal tenesmus, dysphagia and urinary retention. Decreased tear production, dry mucous membranes, bilateral Horner's syndrome, decreased anal sphincter tone and gastrointestinal hypomotility were also observed. Presumptive diagnoses of dysautonomia were made based on the clinical presentation and investigations. Postmortem histopathological examination in one of the cases demonstrated marked depletion of neuronal cell bodies in the intestinal myenteric plexuses and parasympathetic ganglia, confirming the diagnosis in this case. Criteria for aiding the antemortem diagnosis of this rare condition based on clinical observations and diagnostic testing are proposed.

Surfactant alteration and replacement in acute respiratory distress syndrome.

The acute respiratory distress syndrome (ARDS) is a frequent, life-threatening disease in which a marked increase in alveolar surface tension has been repeatedly observed. It is caused by factors including a lack of surface-active compounds, changes in the phospholipid, fatty acid, neutral lipid, and surfactant apoprotein composition, imbalance of the extracellular surfactant subtype distribution, inhibition of surfactant function by plasma protein leakage, incorporation of surfactant phospholipids and apoproteins into polymerizing fibrin, and damage/inhibition of surfactant compounds by inflammatory mediators. There is now good evidence that these surfactant abnormalities promote alveolar instability and collapse and, consequently, loss of compliance and the profound gas exchange abnormalities seen in ARDS. An acute improvement of gas exchange properties together with a far-reaching restoration of surfactant properties was encountered in recently performed pilot studies. Here we summarize what is known about the kind and severity of surfactant changes occurring in ARDS, the contribution of these changes to lung failure, and the role of surfactant administration for therapy of ARDS.

Overproduction of a functional A1 ATPase from the archaeon Methanosarcina mazei Gö1 in Escherichia coli.

Single subunits of the A1 ATPase from the archaeon Methanosarcina mazei Gö1 were produced in E. coli as MalE fusions and purified, and polyclonal antibodies were raised against the fusion proteins. A DNA fragment containing the genes ahaE, ahaC, ahaF, ahaA, ahaB, ahaD, and ahaG, encoding the hydrophilic A1 domain and part of the stalk of the A1AO ATPase of M. mazei Gö1, was constructed, cloned into an expression vector and transformed into different strains of Escherichia coli. In any case, a functional, ATP-hydrolysing A1 ATPase was produced. Western blots demonstrated the production of subunits A, B, C, and F in E. coli, and minicell analyses suggested that subunits D, E, and G were produced as well. This is the first demonstration of a heterologous production of a functional ATPase from an archaeon. The A1 ATPase was sensitive to freezing but lost only about 50% of its activity within 18 days on ice. Inhibitor studies revealed that the heterologously produced A1 ATPase is insensitive to azide, dicyclohexylcarbodiimide and bafilomycin A1, but sensitive to diethylstilbestrol and its analogues dienestrol and hexestrol. The expression system described here will open new avenues towards the functional and structural analyses of this unique class of enzymes.

Ultrasonographic imaging of the vagosympathetic trunk in the dog.

The purpose of this study was to evaluate the applicability of ultrasonographic imaging of the vagosympathetic trunk in the dog. Cervical ultrasound was performed in 30 healthy dogs. In all 30 dogs the vagosympathetic trunk was detected as a hypoechoic structure in the carotid sheath, adhering the dorsomedial surface of the common carotid artery. The echotexture of the nerve was heterogeneous with anechoic areas separated by hypoechoic bands. A scanner equipped with a 5 to 8 MHz linear array probe was used for imaging and measurements. The diameter of the vagosympathetic trunk ranged from 0.59 to 2.48 mm varying in correlation to the body weight. In summary, ultrasonography is a helpful noninvasive method to image and evaluate the cervical vagosympathetic trunk in the dog.

Selective extraction of subunit D of the Na(+)-translocating methyltransferase and subunit c of the A(1)A(0) ATPase from the cytoplasmic membrane of methanogenic archaea by chloroform/methanol and characterization of subunit c of Methanothermobacter thermoautotrophicus as a 16-kDa proteolipid.

Chloroform/methanol was applied to cytoplasmic membranes of the thermophilic methanogens Methanothermobacter thermoautotrophicus and Methanothermobacter marburgensis as well as to the mesophile Methanosarcina mazei Gö1. In any case, the chloroform/methanol extraction yielded only two proteins, subunit D (MtrD) of the Na(+)-translocating methyltetrahydromethanopterin:coenzyme M methyltransferase and the proteolipid of the A(1)A(0) ATPase. Both polypeptides are assumed to be directly involved in ion translocation in their respective enzymes, but have not been studied in detail due to lack of simple isolation procedures. The rapid and selective isolation by chloroform/methanol offers a new way to obtain the large quantities of material required for biochemical analyses. As a first result, molecular and biochemical data suggest that the proteolipid from M. thermoautotrophicus is a duplication of the 8-kDa proteolipid usually present in other archaea, but it retained the conserved glutamate involved in proton translocation in every copy. This is the first 16-kDa proteolipid found in archaea.

Enhanced tissue factor pathway activity and fibrin turnover in the alveolar compartment of patients with interstitial lung disease.

Bronchoalveolar lavage fluids (BALF) from patients with hypersensitivity pneumonitis (HP; n = 35), idiopathic pulmonary fibrosis (IPF, n = 41) and sarcoidosis (SARC, n = 48) were investigated for alterations in the alveolar hemostatic balance. Healthy individuals (n = 21) served as Controls. Procoagulant activity (PCA), tissue factor (TF) activity and F VII activity were assessed by means of specific recalcification assays. The overall fibrinolytic activity (FA) was measured using the (125)I-labeled fibrin plate assay. Fibrinopeptide A (FP-A), D-Dimer, plasminogen activators (PA) of the urokinase (u-PA) or tissue type (t-PA), PA-inhibitor I (PAI-1) and alpha2-antiplasmin (alpha2-AP) were determined by ELISA technique. As compared to Controls, all groups with interstitial lung disease (ILD) displayed an increase in BALF PCA by approximately one order of magnitude, and this was ascribed to enhanced TF activity by >98%. Accordingly, F VII-activity was increased in all ILD groups, and elevated FP-A levels were noted. There was no significant difference in procoagulant activities between the different ILD entities, but the increase in TF was significantly correlated with deterioration of lung compliance. Overall fibrinolytic activity did not significantly differ between ILD entities and Controls, although some reduction in IPF subjects was observed. Nevertheless, changes in the profile of the different pro- and antifibrinolytic compounds were noted. U-PA, but not t-PA levels were significantly reduced in all ILD groups. alpha2-AP was markedly elevated throughout, whereas PAI-1 levels were lowered. As a balance of

Cervical neoplasia originating from the vagus nerve in a dog.

An eight-year-old intact male Bernese mountain dog was referred with a history of chronic vomiting, coughing and signs of respiratory distress. Other historical findings included lethargy, weight loss and choking. On presentation, clinical findings were Horner's syndrome, ipsilateral laryngeal hemiplegia, coughing, gagging, respiratory distress and vomiting. Lateral cervical radiographs showed ill-defined mineralisation in the soft tissue ventral to the third cervical vertebra, while ultrasonography of the neck revealed a well marginated heterogeneous mass with focal hyperechogenic lesions and acoustic shadowing. Results of an ultrasound-guided fine needle aspirate suggested neoplasia. At necropsy, a large tumour was detected in the ventral cervical region, originating from the right vagosympathetic trunk. In view of the infiltrating pattern, the cellular pleomorphism and the numerous mitoses on histopathological examination, the tumour was classified as a malignant peripheral nerve sheath tumour.

Alveolar fibrin formation caused by enhanced procoagulant and depressed fibrinolytic capacities in severe pneumonia. Comparison with the acute respiratory distress syndrome.

Changes in the alveolar hemostatic balance in severe pneumonia were compared with those in the acute respiratory distress syndrome (ARDS). Analysis was performed in bronchoalveolar lavage fluids (BALF) of patients with ARDS triggered by nonpulmonary underlying events in the absence of lung infection (ARDS; n = 25), pneumonia demanding mechanical ventilation (PNEU-vent; n = 114), spontaneously breathing patients with pneumonia (PNEU-spon; n = 40), and ARDS in combination with lung infection (ARDS+PNEU; n = 43); comparison with healthy control subjects (n = 35) was performed. In all groups of patients, BALF total procoagulant activity was increased by nearly two orders of magnitude, being largely attributable to the tissue factor pathway of coagulation. Concomitantly, markedly reduced overall fibrinolytic capacity (fibrin plate assay) was noted in the lavage fluids of all patients. BALF levels of urokinase-type plasminogen activator were significantly reduced throughout, whereas the lavage concentrations of tissue-type plasminogen activator did not differ from those in control subjects. In addition, markedly enhanced levels of plasminogen activator- inhibitor I and alpha(2)-antiplasmin were noted in ARDS, ARDS+PNEU, and PNEU-vent, but not in PNEU-spon. In all groups of patients, the changes in the lavage enzymatic activities were paralleled by manifold increased BALF concentrations of fibrinopeptide A and D-dimer, reflecting in vivo coagulation processes. Within the overall number of patients with pneumonia, changes in the alveolar hemostatic balance were more prominent in alveolar and interstitial pneumonia than in bronchopneumonia. Acute inflammatory lung injury, whether triggered by nonpulmonary systemic events or primary lung infection, is thus consistently characterized by both enhanced procoagulant and depressed fibrinolytic activities in the alveolar lining layer, with the appearance of fibrin formation in this compartment. Profile and extent of changes in severe pneumonia demanding respirator therapy are virtually identical to those in ARDS, whereas somewhat less prominent alterations of the alveolar hemostatic balance are noted in spontaneously breathing patients with pneumonia.

Cleavage of surfactant-incorporating fibrin by different fibrinolytic agents. Kinetics of lysis and rescue of surface activity.

Incorporation of surfactant into polymerizing fibrin causes loss of surface activity and marked retardation of clot lysis by plasmin (Günther and colleagues, Am. J. Physiol. 1994;267:L618-L624). We compared the efficacy of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), activated anisoylated streptokinase-plasminogen activator complex (APSAC), and plasmin to dissolve surfactant-incorporating fibrin. Alveofact was employed as a natural surfactant source, and plasminogen was coincorporated into the fibrin matrix at a physiologic ratio to fibrin. Fibrinolysis was quantified by the release of tracer from (125)I-labeled fibrin, and the pattern of split products was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition, we investigated the fibrinolysis-related restoration of surface activity by measurement in the pulsating bubble surfactometer. Concentrations of all fibrinolytic agents were chosen to effect approximately 40% lysis of clot material in the absence of surfactant (control). When incorporated into the fibrin matrix, but not when admixed after clot formation, surfactant inhibited the cleavage of fibrin by all fibrinolytic agents in a dose-dependent manner. Interestingly, t-PA and u-PA were significantly less inhibited than was plasmin or APSAC. The pattern of arising fibrin scission products was identical for all fibrinolytic approaches and was independent of surfactant incorporation. Adsorption and minimum surface tension-lowering properties of Alveofact were almost completely lost upon incorporation into fibrin, but surface activity was fully restored upon sustained clot lysis with all fibrinolytic agents. We conclude that the fibrinolytic capacity of all agents investigated is markedly inhibited by surfactant incorporation in fibrin, but this inhibition is significantly less pronounced in the agents employing preincorporated plasminogen (t-PA and u-PA), as compared with plasmin and APSAC. The plasminogen activators may thus proffer to "rescue" pulmonary surfactant function by induction of fibrinolysis in the alveolar compartment.

The proteolipid of the A(1)A(0) ATP synthase from Methanococcus jannaschii has six predicted transmembrane helices but only two proton-translocating carboxyl groups.

The proteolipid, a hydrophobic ATPase subunit essential for ion translocation, was purified from membranes of Methanococcus jannaschii by chloroform/methanol extraction and gel chromatography and was studied using molecular and biochemical techniques. Its apparent molecular mass as determined in SDS-polyacrylamide gel electrophoresis varied considerably with the conditions applied. The N-terminal sequence analysis made it possible to define the open reading frame and revealed that the gene is a triplication of the gene present in bacteria. In some of the proteolipids, the N-terminal methionine is excised. Consequently, two forms with molecular masses of 21,316 and 21,183 Da were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The molecular and biochemical data gave clear evidence that the mature proteolipid from M. jannaschii is a triplication of the 8-kDa proteolipid present in bacterial F(1)F(0) ATPases and most archaeal A(1)A(0) ATPases. Moreover, the triplicated form lacks a proton-translocating carboxyl group in the first of three pairs of transmembrane helices. This finding puts in question the current view of the evolution of H(+) ATPases and has important mechanistic consequences for the structure and function of H(+) ATPases in general.