[Muscle, tendon and joint injections : What is the evidence?]

Injections at tendon insertions, in muscles and in joints are an important instrument in the conservative treatment of musculoskeletal diseases, for acute injuries as well as for chronic degenerative diseases. Local anesthetic agents and glucocorticoids are well-established medications; however, severe side effects, such as chondrolysis have sometimes been reported, particularly for local anesthetic agents. In addition platelet rich plasma (PRP) and hyaluronic acid are also widely used; however, the clinical effectiveness has not always been proven. This article gives an overview on the most commonly used medications for injections and the mechanisms of action. The indications for treatment and the evidence for the clinical adminstration of muscle, tendon and joint injections are described based on the currently available literature.

Proton Magnetic Resonance Spectra of Benzene and Benzene-1-13C in Isotropic and in Nematic Solution

Th 1H-NMR-spectra of benzene and benzene-1-13C in the isotropic phase (CCl4 solution) as well as in the nematic phase of a liquid crystal are analysed and the resulting direct and indirect couplings presented. The comparison of observed direct couplings with values calculated from known Raman structural data shows deviations of up to 9% relative to the HH(orto) -coupling. This corresponds to an apparent increase of the carbon-proton distance of 0.03 A. Possible reasons are discussed such as anisotropy of the indirect couplings, solvent effects on indirect couplings and intramolecular vibrations. The conclusion is reached that the consideration of intramolecular vibrational motion perfectly explains the discrepancies.

Thrombin receptor antagonism in antiplatelet therapy

Activated platelets play a crucial role in the pathogenesis of atherothrombotic disease and its complications. Even under treatment of antiplatelet drugs, such as acetylsalicylic acid and P2Y12 antagonists, morbidity and mortality rates of thromboembolic complications remain high. Hence, the therapeutic inhibition of protease-activated receptor (PAR)-1, which is activated by thrombin, is a novel promising approach in antiplatelet therapy. Recent data suggest that PAR-1 is mainly involved in pathological thrombus formation, but not in physiological hemostasis. Therefore, PAR-1 inhibition offers the possibility to reduce atherothrombotic events without increasing bleeding risk. So far, two emerging PAR-1 antagonists have been tested in clinical trials: vorapaxar (SCH530349; Merck & Co., Whitehouse Station, NJ, USA) and atopaxar (E5555; Eisai, Tokyo, Japan). Although in TRA-CER vorapaxar showed an unfavorable profile for patients with acute coronary syndrome in addition to standard therapy, it revealed promising results for patients with prior myocardial infarction in TRA 2P-TIMI50. Depending on the status of clinical approval, vorapaxar might be an option for patients with peripheral arterial disease to reduce limb ischemia. The second PAR-I antagonist, atopaxar, tended towards reducing major cardiovascular adverse events in acute coronary syndrome patients in a phase II trial. However, although statistically not significant, bleeding events were numerically increased in atopaxar-treated patients compared with placebo. Furthermore, liver enzymes were elevated and the relative corrected QT interval was prolonged in atopaxar-treated patients. Currently, the development of atopaxar by Eisai is discontinued. The future of this novel class of antithrombotic drugs will depend on the identification of patient groups in which the risk–benefit ratio is favorable.

[Calcific tendinitis of the shoulder]

Calcific tendinitis of the shoulder is a process involving crystal calcium deposition in the rotator cuff tendons, which mainly affects patients between 30 and 50 years of age. The etiology is still a matter of dispute. The diagnosis is made by history and physical examination with specific attention to radiologic and sonographic evidence of calcific deposits. Patients usually describe specific radiation of the pain to the lateral proximal forearm, with tenderness even at rest and during the night. Nonoperative management including rest, nonsteroidal anti-inflammatory drugs, subacromial corticosteroid injections, and shock wave therapy is still the treatment of choice. Nonoperative treatment is successful in up to 90% of patients. When nonsurgical measures fail, surgical removal of the calcific deposit may be indicated. Arthroscopic treatment provides excellent results in more than 90% of patients. The recovery process is very time consuming and may take up to several months in some cases.

Arbuscular mycorrhizal infection in two morphological root types of Araucaria araucana (Molina) K. Koch

Araucaria araucana (Molina) K. Koch is a conifer distributed in the Andean-Patagonian forests in the south of Argentina and Chile. The main objective of this work was to relate the different root classes appearing in A. araucana to mycorrhizal behavior. Samples were collected in three different sites in the Lanín National Park (NW Patagonia, Argentina). Two different root classes were present in A. araucana: longitudinal fine roots (LFR) and globular short roots (GSR). Both had extensive mycorrhizal arbuscular symbiosis (AM) and presented abundant hyphae and coils in root cells, a characteristic of the anatomical Paris-type. Dark septate fungal endophytes were also observed. Values of total AM colonization were high, with similar partial AM% values for each root class. Seasonal differences were found for total and partial colonization, with higher values in spring compared to autumn. Regarding the percentage of fungal structures between root classes, values were similar for vesicles and arbuscules, but higher coil percentages were observed in GSR compared to LFR. The percentages of vesicles increased in autumn, whereas the arbuscule percentages increased in spring, coinciding with the plant growth peak. Results show that both root classes of A. araucana in Andean-Patagonian forests are associated with AM fungi, which may have ecological relevance in terms of the importance of this symbiosis, in response to soil nutrient-deficiencies, especially high P-retention.

[Haemophilic pseudotumour of the distal femur - a case report and characterisation of this entity]

Haemophilic pseudotumour is a rare disease occurring in 1 % of patients with severe haemophilia as a long-term complication. Because both haemophilia A (factor VIII deficiency) and haemophilia B (factor IX deficiency) are X-linked recessive genetic disorders, pseudotumours are found almost exclusively in men between 20 and 70 years of age. Haemophilic pseudotumour has been defined as a progressive cystic swelling, produced by recurrent haemorrhage, which exerts increasing pressure on nearby structures. As a result, necrosis of skin, muscle and bone can be found. Neurovascular obstruction as well as pathologic fractures are severe complications of this disease. Most patients with pseudotumours are asymptomatic for a long time and many patients report sustaining an injury prior to the development of the tumour. Most haemophilic pseudotumours of the bone are located in the pelvis, femur and hand. We present the case of a 59-year-old male patient suffering from a haemophilic pseudotumour of the right distal femur. After verification of the diagnosis by means of an open biopsy, final surgery with curettage and plombage with bone cement was performed.

[The role of microparticles in vascular diseases]

Microparticles (MP) are small cell vesicles that are released by activated or apoptotic cells and that are amenable to quantification in peripheral blood. MP consist of the cytoplasm and the cell membrane of their cell of origin, which allows for their assignment to these cells. By the detection of the respected MP one can conclude to the functional status of the cell of origin. It is known that MP confer specific information between cells and contribute to inflammatory and coagulatory processes. They are detectable in many acute and chronic vascular diseases as a surrogate marker for disease activity but also play a role in the pathophysiology of vascular diseases.

Die Bedeutung von Mikropartikeln bei vaskulären Erkrankungen

Mikropartikel (MP) sind kleine Zellvesikel, die von Zellen im Rahmen von Aktivierung oder Apoptose freigesetzt werden und im Blut nachweisbar sind. MP bestehen aus Plasma und Zellmembran ihrer Ursprungszelle und können anhand ihrer Oberflächenantigene ihrer Ursprungszelle zugeordnet werden. Durch den Nachweis entsprechender MP kann somit eine Aussage über den Funktionszustand der Ursprungszelle (Aktivierung oder Apoptose) getroffen werden. Mittlerweile ist bekannt, dass MP als Vektoren spezifische biologische Informationen zwischen einzelnen Zellen austauschen können und somit ein wesentliches Bindeglied in der Pathophysiologie inflammatorischer und koagulatorischer Prozesse darstellen. Da viele Gefäßerkrankungen mit inflammatorischen und thrombotischen Prozessen einhergehen, sind MP nachweisbar und bekommen sowohl als Diagnostikum (Surrogatmarker) als auch als pathophysiologischer Baustein vaskulärer Erkrankungen zunehmende Bedeutung.

[Is stent thrombosis the new Achilles heel of interventional cardiology? State of the Art clinical trials, causes and approaches for prevention]

Coronary stents are the mainstay of percutaneous coronary intervention. Stent thrombosis is a potentially catastrophic and often life-threatening complication. If it occurs it presents in up to 80% as myocardial infarction, about half of the affected patients die from this complication. The dual antiplatelet therapy has markedly reduced its occurrence. Today, stent thrombosis occurs in <1%, usually as a delayed event; but compared to bare metal stents the overall incidence has not increased in meta-analyses of randomized trials. The advent of drug-eluting stents (DES) has raised concerns regarding the occurrence of delayed stent thrombosis. Delayed arterial wall healing as well as prothrombotic characteristics of the drug eluting stent itself may contribute to stent thrombosis. In order to prevent stent thrombosis a standardized fixed dose antiplatelet therapy with ASA and clopidogrel is recommended. But, their efficacy depends on patient's individual characteristics such drug metabolism. Therefore, individual determination of platelet function in each patient undergoing stent implantation may help to avoid prothrombotic as well as bleeding complications.

[Diagnostic strategies in cases of suspected periprosthetic infection of the knee. A review of the literature and current recommendations]

Reliable confirmation of periprosthetic infection after total knee arthroplasty is a diagnostic challenge. The present work reviews published data evaluating the available diagnostic tools. Erythrocyte sedimentation rate and C-reactive protein serum levels are relatively sensitive methods with rather low specificity towards periprosthetic infection and are mainly applied to exclude infection. Studies evaluating scintigraphic methods--especially white cell scans--provide inconsistent data with varying accuracy. Consequently, white cell scans cannot be recommended as standard methods. Immunoscintigraphy with antigranulocyte antibodies and FDG-PET scans demonstrated promising results with particularly high sensitivities, but have to be validated in larger studies. Microbiological evaluation of joint aspirates proved high specificity for periprosthetic infection. However, an average of 20% of infected cases remained undetected. Nevertheless, aspiration is widely recommended for preoperative isolation of the infecting organism. Intraoperative frozen sections demonstrated excellent specificity with good sensitivity. The real accuracy of intraoperative culture and permanent histology cannot be determined due to the missing golden standard; however, a combination of both methods is recommended to define the final diagnosis. Large studies validating both methods and criteria for the final diagnosis of periprosthetic infection are necessary to optimize the diagnostic algorithm.

[The modular MML revision system in knee revision and tumor arthroplasty]

Increasing age and a higher level of mobility lead to an increasing incidence in revision arthroplasty after total knee replacement and tumor surgery. So far, the reconstruction of large defects in bony and soft tissue environments can be accomplished by the modern modular components of revision implants. The consecutive reconstruction of the extensor mechanism in extended revision has its own drawbacks and is often associated with significant functional limitations for the patient. Specially designed implants and methods are required to generate good functional results. The modular knee revision system MML provides specific modifications of the tibial component for reconstruction of the extensor mechanism. Combined with artificial strips, an excellent functional outcome could be achieved. In this study, 70 patients were operated with the MML endoprosthesis in knee revision or tumor surgery. An excellent functional outcome could be determined. At 7 years after surgery, an average of 32+/-13 points was achieved on the Oxford Knee Score. The outcome measurement using the functional scoring system of the American Knee Society (AKS score) showed similarly good results with 71+/-25 points out of 100. A minor deficit of only 2 degrees in active extension could be observed after reconstruction of the extensor mechanism. In conclusion, we have demonstrated that the MML modular revision system is appropriate for reconstruction of segmental bone defects.

Ist die Stentthrombose die neue Achillesferse der interventionellen Kardiologie?

Der Einsatz von Koronarstents gehört zu den Grundpfeilern der perkutanen Koronarintervention. Die Stentthrombose ist dabei eine lebensbedrohliche Komplikation. Tritt sie auf, so erleiden bis zu 80% der Betroffenen einen Myokardinfarkt, bis zu 50% versterben. Durch die duale Plättchenaggregationshemmung konnten Stentthrombosen deutlich reduziert werden; die Inzidenz liegt heute unter 1%. Mit dem Aufkommen medikamentenfreisetzender Stents hat sich die Zeitspanne des Auftretens bis hin zu mehreren Jahren nach Implantation verlängert; die Gesamtinzidenz hat sich aber in Metaanalysen der randomisierten Studien nicht erhöht.

Ursächlich ist ein verzögerter vaskulärer Heilungsprozess sowie eine Kontakt- und Medikamenten-assoziierte Thrombozytenaktivierung. Vorbeugend wird daher eine standardisierte duale plättchenhemmende Therapie mit ASS und Clopidogrel empfohlen. Ihre Wirkung hängt von individuellen Faktoren ab. Durch die Bestimmung der Thrombozytenaggregationshemmung würde eine individuelle Dosisanpassung möglich, so dass thrombotische Nebenwirkungen und Blutungskomplikationen verringert werden könnten.

Periprothetische Frakturen nach Knietotalendoprothetik

The increasing implantation rates of knee arthroplasties are associated with a growing prevalence of complications like periprosthetic fractures. Underlying patient, implant and/or operation technique-related risk factors contribute to these fractures which often occur after minor trauma. In the diagnostic process, fracture dislocation, implant stability, and integrity of the extensor mechanism have to be assessed. Valid classification systems are available to guide treatment decisions. Treatment goals are precise reposition, stable fixation, restoration of function, and early mobilization. In the case of an operative revision, the surgeon has to know the implanted device and has to be prepared for extended procedures and revision arthroplasty. Less invasive fixation devices like retrograde nailing or LISS are often sufficient to stabilize femoral supracondylar fractures, while loosening of the implant often requires extended exchange arthroplasty. Tibial fractures are often associated with osteolysis and bone loss which has to be addressed with bone grafts or augmented revision implants. Long-stemmed implants allow bypassing of the reconstructed defect and provide a stable solution for early mobilization. Patella fractures with stable or asymptomatic implants and continuity of the extensor mechanism should be treated conservatively. If reconstruction becomes necessary, results are often associated with significant functional limitations.

[Reconstruction of the extensor tendons in revision total knee arthroplasty and tumor surgery]

Reconstruction of the extensor mechanism in extended revision after total knee replacement and tumor surgery remains a clinically relevant problem. Due to large tibial bone defects with resection of the extensor insertion area, the specific problem of patella ligament refixation frequently arises. Several biological approaches and augmentation techniques have been published. Most of these are associated with a high rate of revision surgery because of failed replacement of the extensor mechanism and unsatisfactory functional outcome. Surgical reconstruction of these tendon defects is complicated by the difficulty of completely neutralizing tensional force across the repair. To overcome this problem, methods have been developed to reinforce the reconstruction with overlapping flaps; in addition, artificial materials are being increasingly used for tension neutralization. These artificial strips need special fixation mechanisms on the tibial component and specific technical modifications of the prosthesis. The present study gives an overview of reconstruction modalities of the extensor mechanism and provides an improved technology for better reconstruction by using artificial strips combined with specific modifications of the tibial component.

[Therapy of arthrofibrosis after total knee arthroplasty]

Arthrofibrosis is one of the most common complications after total knee arthroplasty with an overall incidence of approximately 10%. Nevertheless, published data are rare and clinical trials mostly include small and heterogeneous patient series resulting in controversial conclusions. Clinically, arthrofibrosis after knee arthroplasty is defined as (painful) stiffness with scarring and soft tissue proliferation. Differentiation between local (peripatellar) and generalized fibrosis is therapeutically relevant. Histopathology typically shows subsynovial fibrosis with synovial hyperplasia, chronic inflammatory infiltration, and excessive and unregulated proliferation of collagen and fibroblasts. Diagnostic strategies are based on the exclusion of differential causes for painful knee stiffness, and especially the exclusion of low-grade infections represents a diagnostic challenge. Early and intensive physiotherapy combined with sufficient analgesia should be initiated as a basic therapy. The next therapeutic steps for persisting arthrofibrosis include closed manipulation and open arthrolysis. Arthroscopic interventions should be limited to local fibrosis. Revision arthroplasty represents a rescue surgery, often associated with recurrence of fibrosis. Prevention of arthrofibrosis by sufficient analgesia and early physiotherapy remains the best treatment option for painful stiffness after knee arthroplasty.

Retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis: a short-term, prospective study

In this prospective study, tibiotalocalcaneal arthrodesis was performed in 29 patients with a retrograde femur nail (Interlocking Compression Nail; Stryker Trauma, Schönkirchen, Germany) inserted through a plantar approach. Patients were evaluated by a standardized follow-up examination using the American Foot and Ankle Society ankle-hindfoot scale and the main criteria of the short-form health survey (36 items). Special emphasis was placed on surgical approach, bony consolidation, and postoperative quality of life. Solid fusion was achieved in 90% of the patients after a mean follow-up of 25 months. Twenty-two patients (76%) showed primary bone healing after an average of 5.2 months; a delayed union was observed in 7 patients. In 79% of the patients, pain was reduced effectively and quality of life substantially improved with the intramedullary nail arthrodesis. The average ankle-hindfoot score improved from 46 (range, 41-53) to 71 (range, 49-83) points. Complications occurred in 6 patients (21%), including 2 deep infections, 3 nonunions, and 1 case of postoperative flexion deformity. The authors found retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis to be an effective technique in obtaining solid fusion, an effective relief from pain, and an improvement of quality of life.

[Diagnosis specific differences in knee joint geometry. A challenge for the correct axial implantation of long stems in total knee arthroplasty]

BACKGROUND

Arthrotic deformities with changes in knee geometry can produce difficulties in implanting long stem knee prosthesis systems using intramedullary alignment. They can result in incorrect lower limb axis and prosthesis positioning. The aim of the presented study was to measure knee geometry in patients with varus and valgus gonarthrosis in order to define diagnosis related differences.

METHODS

A total of 75 patients with indication for total knee arthroplasty were divided in two groups using the weight bearing lower limb axis: patients with varus gonarthrosis (n=43) and with valgus gonarthrosis (n=32). Angles and extensions, important for knee prosthesis implantation, were measured, digitalized and analyzed. The results were investigated for diagnosis specific differences.

RESULTS

After regulation of the measured extension in mean femur/tibia lengths, significant diagnosis specific differences were found: femur condyles were widened towards pathologic weight bearing (P<0.044), and the mechanical tibia axis of the varus gonarthrosis group is transferred to the lateral side (P<0.046) and in projection over the lateral internal cortical substance.

CONCLUSION

The significant differences in deformed arthrotic knees indicate that for an optimal postoperative result the use of standard implants is not always sufficient. Modular knee prosthesis systems can provide adequately for individual demands.

The structure and domain organization of Escherichia coli isocitrate lyase

Enzymes of the glyoxylate-bypass pathway are potential targets for the control of many human diseases caused by such pathogens as Mycobacteria and Leishmania. Isocitrate lyase catalyses the first committed step in this pathway and the structure of this tetrameric enzyme from Escherichia coli has been determined at 2.1 A resolution. E. coli isocitrate lyase, like the enzyme from other prokaryotes, is located in the cytoplasm, whereas in plants, protozoa, algae and fungi this enzyme is found localized in glyoxysomes. Comparison of the structure of the prokaryotic isocitrate lyase with that from the eukaryote Aspergillus nidulans reveals a different domain structure following the deletion of approximately 100 residues from the larger eukaryotic enzyme. Despite this, the active sites of the prokaryotic and eukaryotic enzymes are very closely related, including the apparent disorder of two equivalent segments of the protein that are known to be involved in a conformational change as part of the enzyme's catalytic cycle.

Magnetic Resonance of 3He and 129Xe in Aqueous Solutions Containing Paramagnetic Mn2+ and Co2+ Ions. A Comparisonwith Isoelectronic 7Li+ and 133Cs+ Ions

The chemical shifts and relaxation times T

Does standardized mega-code training improve the quality of pre-hospital advanced cardiac life support (ACLS)?

The aim of our prospective study was to evaluate the effects of a standardized mega-code and arrhythmia training upon process elements of quality of pre-hospital advanced cardiac life support provided by a physician-staffed mobile intensive care unit. In 145 cases of adult cardiac arrest due to cardiac aetiology, time intervals from arrival of the mobile intensive care unit at the patient's side until first ECG diagnosis, first defibrillation, endotracheal intubation, and first epinephrine administration were measured with on-line tape recording, prior to, and following a standardized 8-h arrhythmia and mega-code training. Following the training, patients with asystole or pulseless electrical activity were intubated 1.1 min earlier (P = 0.03), and received epinephrine 1.3 min earlier (P = 0.01) than prior to the training. There were no significant differences in time intervals concerning management of ventricular fibrillation or tachycardia. Neither admission nor discharge rates differed significantly before and after the training. Thus, practical training including rhythm analysis and mega-code session improved the performance of our mobile intensive care unit in cases of asystole and pulseless electrical activity, and, hence, process elements of quality.

Quality of on-site performance in prehospital advanced cardiac life support (ACLS)

The aim of our prospective study was to assess the structural and procedural quality of an urban emergency medical services (EMS) system providing prehospital basic and advanced cardiac life support (BLS/ACLS), to compare the onsite performance of physicians and non-physicians in ECG diagnosis and defibrillation, and to identify incidence and causes of avoidable delays in the initial treatment sequences.

METHODS

Between 1 February 1991 and 1 July 1992, 162 on-line tape recordings of prehospital cardiopulmonary resuscitation (CPR) efforts performed by the staff of the EMS system of the city of Mainz were evaluated. After arrival at the patient's side, time intervals to initial ACLS steps (first ECG-diagnosis, first defibrillation, endotracheal intubation, first epinephrine administration) were measured. Times to rhythm identification and countershock by EMT-Ds vs. physicians were compared (Mann-Whitney U-test). Time intervals are presented as median values. One-hundred sixty-two adult patients with out-of-hospital cardiac arrests (ventricular fibrillation [VF] or ventricular tachycardia [VT], 72; asystole or electromechanical dissociation [EMD], 90) receiving CPR by EMTs, EMT-Ds, and physicians of the Mainz EMS were included. Patients with arrests due to non-cardiac aetiologies were excluded.

RESULTS

After arrival at the patient's side, for patients with VF/VT, the EMT-Ds took 1:36 min and the physicians took 1:00 min to obtain the first ECG diagnosis (P = 0.004). The first countershock was delivered within 1:42 min by both EMT-Ds and physicians of the mobile intensive care unit (MICU). After diagnosis was established, the EMT-Ds took 0:08 min to defibrillate, whereas the physicians took 0:36 min (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Early defibrillation by emergency physicians or emergency medical technicians? A controlled, prospective multi-centre study

In a controlled, prospective multi-centre study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany--defibrillation by emergency physicians (EPs)-in order to answer the following questions: can EMTs in a two-tiered emergency medical services (EMS) system with physicians in the field defibrillate earlier than, and as safely as EPs? Does defibrillation by EMTs (study group) affect survival rate and long-term prognosis of patients in ventricular fibrillation (VF), as compared with the current national standards in resuscitation (basic cardiopulmonary resuscitation (CPR) by EMTs, and defibrillation by physicians: control group?

METHODS

Prior to the onset of the study, all EMTs completed retraining in basic life support (BLS). Randomly assessed EMTs were then trained to use semi-automatic defibrillators. With the help of on-line tape recordings, the complete resuscitation sequence was evaluated. Follow-up of the patients was carried out with the help of the Glasgow Coma Scale as well as Pittsburgh Cerebral and Overall Performance Categories.

RESULTS

A total of 159 patients with VF were included in the study. In 121 cases, collapse was witnessed. Of the patients receiving defibrillation by EMTs 25% were discharged from hospital alive, compared to 24% of the patients defibrillated by EPs. Of the study patients 67% were defibrillated within 12 min, while the percentage of control patients was 46%. Study patients were defibrillated earlier (P < 0.01), the return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05), and the rate of patients requiring no adrenalin during resuscitation was higher in the study group (P < 0.05). The total amount of adrenalin administered in the study group was lower (P < 0.05). No statistically significant differences were found concerning the neurologic long-term prognosis.

CONCLUSIONS

In our study, EMT defibrillation was equally effective as defibrillation by EPs, but failed to improve survival rates or long-term outcome of patients in VF significantly, compared to EP defibrillation. Due to a reduction in the time intervals from collapse to defibrillation and to ROSC, as well as in adrenalin doses, by EMT-defibrillation, EMTs in Germany should defibrillate if they reach a patient prior to an EP, provided they have received continuous medical training and supervision.

The importance of four histidine residues in isocitrate lyase from Escherichia coli

By site-directed mutagenesis, substitutions were made for His-184 (H-184), H-197, H-266, and H-306 in Escherichia coli isocitrate lyase. Of these changes, only mutations of H-184 and H-197 appreciably reduced enzyme activity. Mutation of H-184 to Lys, Arg, or Leu resulted in an inactive isocitrate lyase, and mutation of H-184 to Gln resulted in an enzyme with 0.28% activity. Nondenaturing polyacrylamide gel electrophoresis demonstrated that isocitrate lyase containing the Lys, Arg, Gln, and Leu substitutions at H-184 was assembled poorly into the tetrameric subunit complex. Mutation of H-197 to Lys, Arg, Leu, and Gln resulted in an assembled enzyme with less than 0.25% wild-type activity. Five substitutions for H-266 (Asp, Glu, Val, Ser, and Lys), four substitutions for H-306 (Asp, Glu, Val, and Ser), and a variant in which both H-266 and H-306 were substituted for showed little or no effect on enzyme activity. All the H-197, H-266, and H-306 mutants supported the growth of isocitrate lyase-deficient E. coli JE10 on acetate as the sole carbon source; however, the H-184 mutants did not.

[Initial defibrillation by emergency physicians or by first aid assistants? A prospective, comparative multicenter study in outpatients with ventricular fibrillation]

In a controlled prospective randomized study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany (basic life support by EMTs and defibrillation by emergency physicians only) in order to answer the following questions: 1. Does EMT defibrillation improve the survival rate and long-term prognosis of patients in ventricular fibrillation as compared to the current German standards in resuscitation (basic life support by EMTs and defibrillation by emergency physicians)? 2. Are the prerequisites for the use of semiautomatic defibrillators fulfilled in the emergency medical systems (EMS) of the participating centers? METHODS. The study phase includes randomization of 121 adult patients with witnessed cardiac arrest and ventricular fibrillation (VF) as first ECG rhythm. Prior to the onset of the study, all EMTs of the participating EMS systems were retrained in basic life support (BLS) measures. In each center, randomly assessed EMT-Ds (EMTs trained in Defibrillation) were trained to use semiautomatic defibrillators. With the help of one-line tape recording, the time intervals during resuscitation and treatment steps were evaluated. Successfully resuscitated patients were followed up with the help of the Glasgow Coma Scale and the Pittsburgh Cerebral and Overall Performance Categories. RESULTS. From 1 February 1991 until 28 June 1992, 159 patients with VF were randomized. In 121 cases, collapse was witnessed. 25% (14/57) of the patients receiving defibrillation by EMT-Ds (study group = S) were discharged from the hospital alive. In the control group, 52 patients were defibrillated by emergency physicians, following BLS by EMTs [control group 1 = C1; discharged: 29% (15/52)]. Fifty patients received BLS and advanced cardiac life support (ACLS) by the emergency physicians crews [control group 2 = C2; discharged: 18% (9/20)]. In the study group, the median time interval from collapse of the patient until initiation of BLS measures was 7.7 min, 7 min in C1 and 8 min in C2. ACLS measures were initiated significantly earlier (P < 0.05) in the control groups, as compared to the study group [S: 13 min, C1: 11 min; C2: 10.3 min]. Sixty-seven percent (30/45) of the study patients and 46% (36/76) of the control patients were defibrillated within 12 min. Study patients were defibrillated earlier (P < 0.05) (S: 9.9 min; C1: 12.2 min; C2: 12.75 min); return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05) in the study group [S: 14 min; C1: 19 min; C2: 18.2 min] and the number of patients in the study group requiring no epinephrine during resuscitation was higher (P < 0.01) than in the control groups [S: 35.3% (12/34); C1: 10% (4/40); C2: 10.5% (4/38)]. Furthermore, the total amount of epinephrine [mean (+/- standard error)] administered in the study group [S: 2.35 (+/- 0.49) mg; C1: 6.71 (+/- 0.98) mg; C2: 7.71 (+/- 1.31) mg] was significantly lower (P < 0.05). No significant differences in neurological long-term prognosis were found for the groups investigated. CONCLUSION. Neither the initial survival rate the number of patients discharged alive, nor the neurological long-term prognosis was significantly different for any of the groups investigated. Because of apparent differences in indirect prognostic parameters (time interval until ROSC, number of patients requiring no epinephrine) and because of the fact that the time interval to the first defibrillation was reduced by EMT defibrillation, EMT-Ds may perform defibrillation if: (a) they reach the patient before the emergency physician and (b) if they are trained intensively and supervised continuously. In order to increase the efficiency of defibrillation by EMT-Ds, far-reaching changes in our EMS are mandatory: (a) a reduction in the time interval from collapse until initiation of BCLS measures by intensifying layperson CPR training; (b) an increase in the number of emergency units equipped with semiautomatic defibril

Site-directed mutagenesis of lysine 193 in Escherichia coli isocitrate lyase by use of unique restriction enzyme site elimination

By a newly developed double-stranded mutagenesis technique, histidine (H), glutamate (E), arginine (R) and leucine (L) have been substituted for the lysyl 193 residue (K-193) in isocitrate lyase from Escherichia coli. The substitutions for this residue, which is present in a highly conserved, cationic region, significantly affect both the Km for Ds-isocitrate and the apparent kcat of isocitrate lyase. Specifically, the conservative substitutions, K-193-->H (K193H) and K193R, reduce catalytic activity by ca. 50- and 14-fold, respectively, and the nonconservative changes, K193E and K193L, result in assembled tetrameric protein that is completely inactive. The K193H and K193R mutations also increase the Km of the enzyme by five- and twofold, respectively. These results indicate that the cationic and/or acid-base character of K193 is essential for isocitrate lyase activity. In addition to the noted effects on enzyme activity, the effects of the mutations on growth of JE10, an E. coli strain which does not express isocitrate lyase, were observed. Active isocitrate lyase is necessary for E. coli to grow on acetate as the sole carbon source. It was found that a mutation affecting the activity of isocitrate lyase similarly affects the growth of E. coli JE10 on acetate when the mutated plasmid is expressed in this organism. Specifically, the lag time before growth increases over sevenfold and almost twofold for E. coli JE10 expressing the K193H and K193R isocitrate lyase variants, respectively. In addition, the rate of growth decreases by almost 40-fold for E. coli JE10 cells expressing form K193H and ca. 2-fold for those expressing the K193R variants. Thus, the onset and rate of E. coli growth on acetate appears to depend on isocitrate lyase activity.

[The emergency telephone number--the essential weak link in an emergency system. Prospective studies involving cardiac arrests observed by bystanders]

The first link in the "chain of survival" concept is the activation of the emergency medical system (EMS) by a bystander after recognition of cardiac arrest (CA) or its immediate prodrome. Our ongoing study is aimed at evaluating the current effectiveness of bystander EMS activation for all cases of CA in the city and area of Mainz. Methods. Starting February 1991, we began to prospectively examine collapse-intervention intervals in all cases of CA treated by our physician-manned ambulance. Precision voice recorders carried by the ambulance crews are activated and linked to the EMS dispatcher to time the arrival of the ambulance vehicle. Time intervals starting from the time of collapse are then reconstructed from the dispatcher's time and the tapes. The emergency phone number dialled initially by the bystander and the time of collapse in witnessed cardiac arrests are identified. RESULTS. Sixty-six CAs were witnessed and included in this study. In 20% of those cases, the number dialled initially by the bystander was 19222 (EMS dispatcher), in 38% 110 (police), and in 42% other numbers (family practitioners or their on-call service, fire department). The time interval, as median (25th percentile; 75th percentile), between collapse and receipt call by the emergency dispatchers was 4 min (2; 8) for all patients (n = 66), and 6.5 min (3; 12) whenever numbers other than emergency phone numbers were dialled. All following time intervals (start of BLS or ACLS procedures) showed differences (P less than 0.05) between the 110 or 19222 group [BLS: 8.5 min (4.8; 13.1) or 10 min (7.35; 12.1); ACLS: 11.3 min (9.1; 13.45) or 12.9 min (10.6; 21.5)] vs the group, in which other phone numbers were initially dialled [BLS: 15.25 min (9.25; 19.4); ACLS: 20.11 min (12.6; 28.3)]. The first ECG rhythm showed VF in 56% and 54% in case 110 and 19222 were dialled, but only in 32% in the other group. CONCLUSION. Even one single weak link in the "chain of survival" can lower overall survival rates. An indispensable, but apparently underrated component of an effective EMS includes an informed citizenry able to call swiftly for help. Lack of an unequivocal emergency number, well known and accepted by the citizens, produces confusion and delays. In our systems, the correct medical emergency phone number (19222) was dialled in 20% of the cases only, thus demonstrating clearly the lack of public awareness of this 5-digit number. In a higher percentage, the three-digit police number (110) was dialled. In cases where numbers other than emergency numbers were dialled (42%), the longest time intervals between collapse and receipt of call by the dispatchers occurred, associated with the longest time intervals until initiation of CPR and the lowest percentage of patients found in ventricular fibrillation. We conclude that establishment of a simple three-digit EMS phone number, preferentially Europe-wide, in combination with an intensification of public awareness, could be a vital step not only to reduce time intervals between collapse and CPR in our EMS system but also to improve survival.

[Rectal administration of drugs. Fundamentals and applications in anesthesia]

Rectal administration of drugs has become a standard procedure in clinical anesthesia, most notably for anorectal induction in children. Limitations of this method include low bioavailability, a wide scatter of pharmacokinetic and pharmacological results, and poor predictability of the clinical effect in any particular patient. Historically, the rectal route has been used for the administration of smoke ("fumigation") for resuscitation and various other purposes. An ether boiler for rectal application was developed by Pirogoff as early as 1847. The pharmacokinetics of rectally administered drugs are determined by the anatomical properties of the rectum and, owing to interindividual variance, this adds to the inconsistency of absorption. Aspects that can be better controlled include the drug preparation and the vehicle, with hydrophilic solutions resulting in improved absorption. Larger volumes such as are associated with lower concentrations increase the bioavailability by enlarging the mucosal surface in contact with the drug. In contrast to the hypothetical assumption that hepatic circulation may be circumvented--thus avoiding first-pass metabolism--by direct venous drainage from the rectum into the systemic circulation via the vena cava, it has been shown that hepatic clearance is the main factor affecting bioavailability. This may be due to blood flow through anastomoses interconnecting the superior, medium and inferior rectal venous systems. Resorption from the rectum is also determined by physicochemical properties of drugs. According to the pH-partition hypothesis, only the non-ionized moiety of a compound will be available for transmucosal diffusion. The degree of ionization is a function of the local (or microclimate) milieu pH and pKa of the drug; the former is close to neutral in adults but alkaline in most children. Adsorption of feces, intraluminal degradation by microorganisms, metabolism within the mucosal cell, and lymphatic drainage do not significantly affect the fate of rectally administered drugs. In clinical practice, the rectal administration of methohexital and midazolam is an established method of premedication or induction of anesthesia in children; so far, midazolam appears to be associated with fewer complications. Ketamine has been shown to be as effective and as quick-acting as methohexital, but at least in one study its use as sole induction agent was associated with respiratory distress in some cases. However, painful diagnostic or therapeutic procedures in children may be indications for the rectal administration of ketamine. Early trials with rectally administered etomidate have been abandoned since its implication in suppression of cortisol synthesis. Narcotic analgesics in a hydrogel vehicle are effective in adult pain management.(ABSTRACT TRUNCATED AT 400 WORDS)