[Navigated retrograde drilling in Osteochondrosis dissecans (OCD) of the talus]. / Navigierte retrograde Anbohrung bei Osteochondrosis dissecans (OCD) des Talus.

OBJECTIVE: Subchondral decompression and revascularization in Osteochondrosis dissecans (OCD) of the talus with cartilage preservation. INDICATIONS: Symptomatic talar OCD stage I and II, i.e., cartilage intact or almost intact. CONTRAINDICATIONS: Talar OCD stage III and IV, i.e., cartilage not intact. SURGICAL TECHNIQUE: Diagnostic ankle arthroscopy. Insertion of dynamic reference base (DRB) in the talar neck through a stab incision. After 3D image acquisition and planning of the drilling, navigated drilling with a 5 mm drill. Insertion of a 1 mm titanium wire into the canal and 3D image acquisition for evaluation of the canal. Autologous cancellous bone transplantation into the canal. Arthroscopic evaluation. POSTOPERATIVE MANAGEMENT: For 6 weeks, 15 kg partial weight bearing without immobilization. After 6 weeks full weight bearing. RESULTS: A total of 52 patients with symptomatic talar OCD stage I and II were included in a clinical follow-up study. Time needed for preparation, including the placement of the DRB, scanning time, and preparation of the trajectories was 7 min 32 s (4-30 min). In 50 cases (96%), the drilling was judged with 3D imaging to be correct. In the remaining 2 cases (4%), the drilling ended in the caudal portion of the lesion. A perforation of the cartilage was not registered arthroscopically. Follow-up after 12 months (range 6-36 months) was possible in 48 patients (92%). Three patients (6%) had been converted to bone cartilage transplantation (OATS) due to recurrent symptoms. These patients were excluded from follow-up. The follow-up scores were Visual Analogue Scale Foot and Ankle (mean 93 points [range 86-100 points]) and the SF 36 (standardized to 100 point maximum, 90 points [range 79-100 points]).

[Entrapped motorists and air rescue services: analysis of tactical rescue approach, rescue techniques, and emergency medical services illustrated by a helicopter emergency medical service]. / Eingeklemmte Fahrzeuginsassen in der Luftrettung: Einsatztaktik, rettungstechnische und notfallmedizinische Analyse am Beispiel einer Rettungshubschrauberstation.

BACKGROUND: Analysis of the results and presentation of a treatment concept of a helicopter emergency medical service (HEMS) in prehospital acute care of entrapped motorists. METHODS: Consecutive patient data collection from primary rescue missions of a helicopter emergency medical service (HEMS) from the years 2000-2004. Evaluation based on data collected regarding emergency medical care, rescue techniques, and tactical rescue approach. RESULTS: A total of 359 cases of entrapped motorists were documented: 237 patients were male, 122 were female, and the average age was 37 (range: 2-82 years). The motor vehicle accidents (MVA) occurred in 21% of the cases on the highway, in 29% on a main road, in 43% on a rural road, and in 7% in city/urban areas. Concerning the vehicle types, 86% were automobiles, 5% vans, and 9% trucks. Drivers accounted for 86% of the patients, front seat passengers for 10.1%, and back seat passengers for 3.9%. The average length of motorist entrapment amounted to 17 min with an average on-scene time of 27 min for the HEMS. The total rescue time averaged 56 min. A Glasgow Coma Scale (GCS) score between 3 and 8 was recorded in 33.7% of the patients; in 24% of the cases the shock index was <1; a respiratory rate of <10/min or >20/min was documented in 25.2% of the patients. An NACA score between I and III was recorded in 34.2% of the cases, NACA IV in 18.9%, and NACA >/=V in 46.8%; 11.9% of the patients died before hospital admission. CONCLUSION: For both the emergency control center personnel and the emergency medical technicians (EMT), a case of motorist entrapment must be considered as a trigger mechanism of injury, activating a sophisticated and time-sensitive prehospital acute care and transportation service. In the German emergency medical service this involves primarily the HEMS. Even in cases of potentially critically injured entrapped motorists, the prehospital adherence to"the golden hour of shock" is made possible, despite the resulting higher personnel and equipment expenses.

Polyaxially-locked plate screws increase stability of fracture fixation in an experimental model of calcaneal fracture.

Different calcaneal plates with locked screws were compared in an experimental model of a calcaneal fracture. Four plate models were tested, three with uniaxially-locked screws (Synthes, Newdeal, Darco), and one with polyaxially-locked screws (90 degrees +/- 15 degrees ) (Rimbus). Synthetic calcanei were osteotomised to create a fracture model and then fixed with the plates and screws. Seven specimens for each plate model were subjected to cyclic loading (preload 20 N, 1000 cycles at 800 N, 0.75 mm/s), and load to failure (0.75 mm/s). During cyclic loading, the plate with polyaxially-locked screws (Rimbus) showed significantly lower displacement in the primary loading direction than the plates with uniaxially-locked screws (mean values of maximum displacement during cyclic loading: Rimbus, 3.13 mm (sd 0.68); Synthes, 3.46 mm (sd 1.25); Darco, 4.48 mm (sd 3.17); Newdeal, 5.02 mm (sd 3.79); one-way analysis of variance, p < 0.001). The increased stability of a plate with polyaxially-locked screws demonstrated during cyclic loading compared with plates with uniaxially-locked screws may be beneficial for clinical use.

[Restoration of the ability to walk through bilateral triple arthrodesis in marked spastic pes equinovarus]. / Wiederherstellung der Gehfähigkeit durch beidseitige Korrekturtriplearthrodese bei hochgradigem Pes equinovarus und Tetraspastik. "Mutti muss laufen"

A tendon transfer is the method of choice in easily reducible pes equinovarus. However, in long-time persisting deformities with spasms, a plantigrade position can not be maintained with these procedures. Therefore, we perform an additional bilateral triple arthrodesis in a patients with such bilateral deformities. A 55-year-old woman developed, within the scope of several surgical procedures on the cervical spine, marked bilateral pes equinovarus and flexion contractures of the knees. The patient's ambulation was limited to a wheelchair for 3 years. Then, in an interval of 1 year, we performed an unilateral soft tissue release, z-tenotomy of the Achilles tendon, triple arthrodesis with correction of the deformity, and posterior tibial tenden transfer. At follow-up 5 years after the second procedure, the 61-year-old patient was able to walk alone with two walking sticks. In the case described, the correction of a marked pes equinovarus with spasms, which was achieved by an extensive soft tissue release, could be stabilized through a triple arthrodesis in such way that the plantigrade position of the foot could be controlled through a posterior tibial tendon transfer.

Pulsed EPR spectroscopy on short-lived intermediates in Photosystem I.

The application of pulsed electron paramagnetic resonance spectroscopy on short-lived intermediates in Photosystem I is reviewed. The spin polarization in light-induced radical pairs gives rise to a phase shifted 'out-of-phase' electron spin echo signal. This echo signal shows a prominent modulation of its intensity as a function of the spacing between the two microwave pulses. Its modulation frequency is determined by the electron-electron spin couplings within the radical pair. Thereby, the measurement of the dipolar coupling gives direct information about the spin-spin distance and can therefore be used to determine cofactor distances with high precision. Application of this technique to the radical pair P(*+)(700)A(*-)(1) in Photosystem I is discussed. Moreover, if oriented samples (e.g. single crystals) are used, the angular dependence of the dipolar coupling can be used to derive the orientation of the axis connecting donor and acceptor with respect to an external (crystal) axes system. Using out-of-phase electron spin echo envelope modulation spectroscopy, the localization of the secondary acceptor quinone A(1) has become possible.

Long-term effects of spontaneous breathing during ventilatory support in patients with acute lung injury.

Improved gas exchange has been observed during spontaneous breathing with airway pressure release ventilation (APRV) as compared with controlled mechanical ventilation. This study was designed to determine whether use of APRV with spontaneous breathing as a primary ventilatory support modality better prevents deterioration of cardiopulmonary function than does initial controlled mechanical ventilation in patients at risk for acute respiratory distress syndrome (ARDS). Thirty patients with multiple trauma were randomly assigned to either breathe spontaneously with APRV (APRV Group) (n = 15) or to receive pressure-controlled, time-cycled mechanical ventilation (PCV) for 72 h followed by weaning with APRV (PCV Group) (n = 15). Patients maintained spontaneous breathing during APRV with continuous infusion of sufentanil and midazolam (Ramsay sedation score [RSS] of 3). Absence of spontaneous breathing (PCV Group) was induced with sufentanil and midazolam (RSS of 5) and neuromuscular blockade. Primary use of APRV was associated with increases (p < 0.05) in respiratory system compliance (CRS), arterial oxygen tension (PaO2), cardiac index (CI), and oxygen delivery (DO2), and with reductions (p < 0.05) in venous admixture (QVA/QT), and oxygen extraction. In contrast, patients who received 72 h of PCV had lower CRS, PaO2, CI, DO2, and Q VA/Q T values (p < 0.05) and required higher doses of sufentanil (p < 0.05), midazolam (p < 0.05), noradrenalin (p < 0.05), and dobutamine (p < 0.05). CRS, PaO2), CI and DO2 were lowest (p < 0.05) and Q VA/Q T was highest (p < 0.05) during PCV. Primary use of APRV was consistently associated with a shorter duration of ventilatory support (APRV Group: 15 +/- 2 d [mean +/- SEM]; PCV Group: 21 +/- 2 d) (p < 0.05) and length of intensive care unit (ICU) stay (APRV Group: 23 +/- 2 d; PCV Group: 30 +/- 2 d) (p < 0.05). These findings indicate that maintaining spontaneous breathing during APRV requires less sedation and improves cardiopulmonary function, presumably by recruiting nonventilated lung units, requiring a shorter duration of ventilatory support and ICU stay.

Recruitment of a foreign quinone into the A1 site of photosystem I. In vivo replacement of plastoquinone-9 by media-supplemented naphthoquinones in phylloquinone biosynthetic pathway mutants of Synechocystis sp. PCC 6803.

Interruption of the phylloquinone (PhQ) biosynthetic pathway by interposon mutagenesis of the menA and menB genes in Synechocystis sp. PCC 6803 results in plastoquinone-9 (PQ-9) occupying the A(1) site and functioning in electron transfer from A(0) to the FeS clusters in photosystem (PS) I (Johnson, T. W., Shen, G., Zybailov, B., Kolling, D., Reategui, R., Beauparlant, S., Vassiliev, I. R., Bryant, D. A., Jones, A. D., Golbeck, J. H., and Chitnis, P. R. (2000) J. Biol. Chem. 275, 8523-8530. We report here the isolation of menB26, a strain of the menB mutant that grows in high light by virtue of a higher PS I to PS II ratio. PhQ can be reincorporated into the A(1) site of the menB26 mutant strain by supplementing the growth medium with authentic PhQ. The reincorporation of PhQ also occurs in cells that have been treated with protein synthesis inhibitors, consistent with a displacement of PQ-9 from the A(1) site by mass action. The doubling time of the menB26 mutant cells, but not the menA mutant cells, approaches the wild type when the growth medium is supplemented with naphthoquinone (NQ) derivatives such as 2-CO(2)H-1,4-NQ and 2-CH(3)-1,4-NQ. Since PhQ replaces PQ-9 in the supplemented menB26 mutant cells, but not in the menA mutant cells, the phytyl tail accompanies the incorporation of these quinones into the A(1) site. Studies with menB26 mutant cells and perdeuterated 2-CH(3)-1,4-NQ shows that phytylation occurs at position 3 of the NQ ring because the deuterated 2-methyl group remains intact. Therefore, the specificity of the phytyltransferase enzyme is selective with respect to the group present at ring positions 2 and 3. Supplementing the growth medium of menB26 mutant cells with 1,4-NQ also leads to its incorporation into the A(1) site, but typically without either the phytyl tail or the methyl group. These findings open the possibility of biologically incorporating novel quinones into the A(1) site by supplementing the growth medium of menB26 mutant cells.

Major secondary surgery in blunt trauma patients and perioperative cytokine liberation: determination of the clinical relevance of biochemical markers.

BACKGROUND: The aim of this study is to assess the associations between the timing of secondary definitive fracture surgery on inflammatory changes and outcome in the patient with multiple injuries. The study population consists of a series of patients with multiple injuries who were managed using a strategy of primary temporary skeletal stabilization followed by delayed definitive fracture fixation. METHODS: In a prospective cohort study performed at a Level I trauma center, the patients' injuries and operative details as well as immune markers and clinical outcomes were studied. The patients were split into an early secondary surgery group (group ESS, surgery at days 2-4) and a late secondary surgery group (group LSS, surgery at days 5-8). During the posttraumatic course, inflammatory markers (interleukin [IL]-6, tumor necrosis factor-alpha) were determined on a daily basis. Perioperatively, these markers were additionally evaluated at 30 minutes, 7 hours, and 24 hours after initiation of surgery. RESULTS: Secondary surgery on days 2 to 4 was associated with a higher incidence of postoperative organ dysfunction (n = 33 [46.5%]) than secondary surgery on days 5 to 8 (n = 9 [15.7%], p = 0.01). A significant association between the combination of initial IL-6 values > 500 pg/dL plus surgery on days 2 to 4 and the development of multiple organ failure (r = 0.96, p < 0.001) occurred. A correlation between the initial IL-6 values > 500 pg/dL and surgery on days 5 to 8 (r = 0.57, p < 0.07) could not be found. IL-6 also demonstrated a predictive value for the development of multiple organ failure: IL-6 > 500 pg/dL in group ESS, r = 0.96, p < 0.001; IL-6 > 500 pg/dL in group LSS, r = 0.57, p < 0.07. CONCLUSION: According to our data, no distinct clinical advantage in carrying out secondary definitive fracture fixation early could be determined. In contrast, in patients who demonstrated initial IL-6 values above 500 pg/dL, it may be advantageous to delay the interval between primary temporary fracture stabilization and secondary definitive fracture fixation for more than 4 days. In patients with blunt multiple injuries undergoing primary temporary fixation of major fractures, the timing of secondary definitive surgery should be carefully selected, because it may act as a second hit phenomenon and cause a deterioration of the clinical status.

Recruitment of a foreign quinone into the A(1) site of photosystem I. II. Structural and functional characterization of phylloquinone biosynthetic pathway mutants by electron paramagnetic resonance and electron-nuclear double resonance spectroscopy.

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance studies of the photosystem (PS) I quinone acceptor, A(1), in phylloquinone biosynthetic pathway mutants are described. Room temperature continuous wave EPR measurements at X-band of whole cells of menA and menB interruption mutants show a transient reduction and oxidation of an organic radical with a g-value and anisotropy characteristic of a quinone. In PS I complexes, the continuous wave EPR spectrum of the photoaccumulated Q(-) radical, measured at Q-band, and the electron spin-polarized transient EPR spectra of the radical pair P700(+) Q(-), measured at X-, Q-, and W-bands, show three prominent features: (i) Q(-) has a larger g-anisotropy than native phylloquinone, (ii) Q(-) does not display the prominent methyl hyperfine couplings attributed to the 2-methyl group of phylloquinone, and (iii) the orientation of Q(-) in the A(1) site as derived from the spin polarization is that of native phylloquinone in the wild type. Electron spin echo modulation experiments on P700(+) Q(-) show that the dipolar coupling in the radical pair is the same as in native PS I, i.e. the distance between P700(+) and Q(-) (25.3 +/- 0.3 A) is the same as between P700(+) and A(1)(-) in the wild type. Pulsed electron-nuclear double resonance studies show two sets of resolved spectral features with nearly axially symmetric hyperfine couplings. They are tentatively assigned to the two methyl groups of the recruited plastoquinone-9, and their difference indicates a strong inequivalence among the two groups when in the A(1) site. These results show that Q (i) functions in accepting an electron from A(0)(-) and in passing the electron forward to the iron-sulfur clusters, (ii) occupies the A(1) site with an orientation similar to that of phylloquinone in the wild type, and (iii) has spectroscopic properties consistent with its identity as plastoquinone-9.

Electron paramagnetic resonance studies of zinc-substituted reaction centers from Rhodopseudomonas viridis.

The primary quinone acceptor radical anion Q(A)(-)(*) (a menaquinone-9) is studied in reaction centers (RCs) of Rhodopseudomonas viridis in which the high-spin non-heme Fe(2+) is replaced by diamagnetic Zn(2+). The procedure for the iron substitution, which follows the work of Debus et al. [Debus, R. J., Feher, G., and Okamura, M. Y. (1986) Biochemistry 25, 2276-2287], is described. In Rps. viridisan exchange rate of the iron of approximately 50% +/- 10% is achieved. Time-resolved optical spectroscopy shows that the ZnRCs are fully competent in charge separation and that the charge recombination times are similar to those of native RCs. The g tensor of Q(A)(-)(*) in the ZnRCs is determined by a simulation of the EPR at 34 GHz yielding g(x) = 2.00597 (5), g(y) = 2.00492 (5), and g(z) = 2.00216 (5). Comparison with a menaquinone anion radical (MQ(4)(-)(*)) dissolved in 2-propanol identifies Q(A)(-)(*) as a naphthoquinone and shows that only one tensor component (g(x)) is predominantly changed in the RC. This is attributed to interaction with the protein environment. Electron-nuclear double resonance (ENDOR) experiments at 9 GHz reveal a shift of the spin density distribution of Q(A)(-)(*) in the RC as compared with MQ(4)(-)(*) in alcoholic solution. This is ascribed to an asymmetry of the Q(A) binding site. Furthermore, a hyperfine coupling constant from an exchangeable proton is deduced and assigned to a proton in a hydrogen bond between the quinone oxygen and surrounding amino acid residues. By electron spin-echo envelope modulation (ESEEM) techniques performed on Q(A)(-)(*) in the ZnRCs, two (14)N nuclear quadrupole tensors are determined that arise from the surrounding amino acids. One nitrogen coupling is assigned to a N(delta)((1))-H of a histidine and the other to a polypeptide backbone N-H by comparison with the nuclear quadrupole couplings of respective model systems. Inspection of the X-ray structure of Rps. viridis RCs shows that His(M217) and Ala(M258) are likely candidates for the respective amino acids. The quinone should therefore be bound by two H bonds to the protein that could, however, be of different strength. An asymmetric H-bond situation has also been found for Q(A)(-)(*) in the RC of Rhodobacter sphaeroides. Time-resolved electron paramagnetic resonance (EPR) experiments are performed on the radical pair state P(960)(+) (*)Q(A)(-)(*) in ZnRCs of Rps. viridis that were treated with o-phenanthroline to block electron transfer to Q(B). The orientations of the two radicals in the radical pair obtained from transient EPR and their distance deduced from pulsed EPR (out-of-phase ESEEM) are very similar to the geometry observed for the ground state P(960)Q(A) in the X-ray structure [Lancaster, R., Michel, H. (1997) Structure 5, 1339].

Determination of the distance between Y(Z)ox* and QA-* in photosystem II by pulsed EPR spectroscopy on light-induced radical pairs.

Out-of-phase electron spin echo envelope modulation (ESEEM) spectroscopy was used to determine the distances within two consecutive radical pair states initiated by a laser flash in photosystem II membrane fragments at pH 11. The distance between the spin density centers of the primary electron donor cation radical, P680+*, and the reduced plastoquinone acceptor, QA-*, has been found to be 27.7+/-0.7 A in agreement with previous results. Near room temperature and at high pH, P680+* is reduced by Y(Z), a redox active tyrosine residue, on a sub-microsecond timescale. As a consequence, the subsequent radical pair state, Y(Z)ox*-QA-*, could be investigated after almost complete reduction of P680+* by Y(Z). The determined dipolar electronic spin-spin coupling within the radical pair Y(Z)ox*QA-* corresponds to a distance of 34+/-1 A between the two molecules.

Long term results after multiple injuries including severe head injury.

OBJECTIVE: To describe the long term results in patients with multiple injuries including severe head injury. DESIGN: Retrospective and prospective clinical study. SETTING: Level I trauma centre, Germany. PATIENTS: Patients aged 16-60 years who had been injured more than 2 years before, whose Injury Severity Score was over 20 and whose cranial Abbreviated Injury Score (AIS) was over 3. MAIN OUTCOME MEASURES: Glasgow Outcome Scale (GOS), functional, neuropsychological, vocational and social outcomes. RESULTS: 58 patients, median age 24 (range 16-53, interquartile range (IQR) 21-32) years were investigated 5 (3-9; IQR 4-7) years after their injury. Median ISS was 34 (21-57; IQR 26-41) and GCS 6 (3-8; IQR 4-7). Duration of coma was 10 (2-51; IQR 7-22) days and neurological rehabilitation lasted 169 (10-830; IQR 80-300) days. Movements of the elbow and ankle was most impaired by injury. All psychometric tests showed deficits, particularly in speed of processing, concentration, recent memory, and learning performance. The social environment had been changed in half and vocational rehabilitation was dependent on age. 24 (42%) returned to their former profession, 18 (31%) were retrained to another profession, 16 (27%) were unemployed or retired on a pension. 31 (53%) made a good recovery with moderate disability, 19 (33%) had severe disability, and 8 (14%) remained in a persistent vegetative state assessed by the GOS. CONCLUSION: Early and concentrated rehabilitation facilitates functional, social, and neuropsychological reintegration.

Pulsed EPR structure analysis of photosystem I single crystals: localization of the phylloquinone acceptor.

A novel application of electron paramagnetic resonance (EPR) is reported to gain three dimensional structural information on cofactors in proteins. The method is applied here to determine the unknown position of the electron acceptor QK, a phylloquinone (vitamin K1), in the electron transfer chain in photosystem I of oxygenic photosynthesis. The unusual electron spin echo (out-of-phase echo) observed for the light induced radical pair P700.+QK.- in PS I allows the measurement of the dipolar coupling between the two radical pair spins which yields directly the distance between these two radicals. Full advantage of the information in the out-of-phase echo modulation can be taken if measurements using single crystals are performed. With such samples, the orientation of the principal axis of the dipolar interaction, i.e., the axis connecting P700.+QK.-, can be determined with respect to the crystal axes system. An angle of theta = (27 +/- 5)degrees between the dipolar coupling axis and the crystallographic c-axis has been derived from the modulation of the out-of-phase echo. Furthermore, the projection of the dipolar axis into the crystallographic a,b-plane, is found to be parallel to the a-axis. The results allow for the determination of two possible locations of QK within the electron transfer chain of photosystem I. These two positions are related to each other by the pseudo C2 symmetry of the chlorophyll cofactors.

Pulsed EPR measurement of the distance between P680+. and Q(A)-. in photosystem II.

Out-of-phase electron spin echo envelope modulation (ESEEM) spectroscopy was used to determine the distance between the primary donor radical cation P680+. and the quinone acceptor radical anion Q(A)-. in iron-depleted photosystem II in membrane fragments from spinach that are deprived of the water oxidizing complex. Furthermore, a lower limit for the distance between the oxidized tyrosine residue Y(Z) of polypeptide D1 and Q(A)-. could be estimated by a comparison of data gathered from samples where the electron transfer from Y(Z) to P680+. is either intact or blocked by preillumination in the presence of NH2OH.

Measurement of cofactor distances between P700.+ and A1.- in native and quinone-substituted photosystem I using pulsed electron paramagnetic resonance spectroscopy.

The radical pair P700.+Q.- (P700 = primary electron donor, Q = quinone acceptor) in native photosystem I and in preparations in which the native acceptor (vitamin K1) is replaced by different quinones is investigated by pulsed EPR spectroscopy. In a two-pulse experiment, the light-induced radical pair causes an out-of-phase electron spin echo, showing an envelope modulation. From the modulation frequency, the dipolar coupling, and therefore the distance between the two cofactors, can be derived. The observation of nearly identical distances of about 25.4 A between P700.+ and Q.- in all preparations investigated here leads to the conclusion that the reconstituted quinones are bound to the native A1 binding pocket. Since the orientation of the reconstituted naphthoquinone relative to the axis joining P700.+ and Q*- differs drastically from that of the native vitamin K1, it cannot be bonded to the protein in the same way as the native acceptor. This implies that the function of A1 as an electron acceptor does not depend on the orientation or hydrogen bonding of the quinone.